Short version, how to use TO and FROM images:
Download, print both.
Glue the one with ring of numbers to cardboard or foam core.
Copy the one with the arrow onto transparency, cut it out.
Pin them together at the central dot.
To use it during travels, carry with you a wristwatch set to your former, accustomed time zone. This serves as a proxy for your internal body clock which presumably will not reset during your travels because you will not be exposed to much bright light. Don't reset the watch before you reset your body clock. Reset your body clock at destination as follows.
The best understood way to correct jetlag uses sunlight on the eyes to reset the body clock in your brain. The amount of shift depends on the time of exposure. This world map helps you pick the time when the shift is the number of time zones you crossed. Turn the transparent map to put your FROM city (on the transparent overlay) in the same radial wedge (time zone) as your TO-city (on the opaque cardboard). The radial arrow from the South Pole (grommet) is the International Date Line. It points to the hour on your FROM-city wristwatch when you can best start resetting your brain's circadian clock by seeing as much sunlight as possible: ideally, a few hours without clouds or sunglasses. The hours are indicated on a scale 0 to 23 like a newscaster's clock: 14 means 2 PM. Make sure you know whether your wristwatch is reading 2 PM or 2 AM. As a check against that mistake, words around the outer rim tell you roughly what part of the local day this will be in the time zone you placed under your FROM-city ... i.e., near your TO-city. This indication is left vague because it is affected by political deviations of time zone boundaries, daylight savings time, etc. Your FROM-city wristwatch is more reliable; reset it only after resetting your brain clock.
An example: Rotate Miami on the transparent FROM map to nearly overlay Tokyo on the opaque TO map. The arrow says to start sunlight exposure at hour 01 (1 AM) on to your Miami- time wristwatch. That will be in Tokyo's late afternoon. After a week in Tokyo your body clock's home time base is Tokyo time. Returning to Miami with your wristwatch now on Tokyo time, rotate Tokyo (FROM) over Miami (TO) and read hour 2, which will be about noon in Miami. At Tokyo hour 2 reset your self, then your wristwatch, to Miami time.
Remember that it is not a good idea to look directly at the sun, even briefly: they eye is easily damaged. And if you are taking medications that make you sensitive to sunlight, or even if you have a fair complexion and you are not accustomed to long bright exposures, you might be better off to just live with your jet-lag.
Addendum:
Here is a problem you might often confront, unless your airport or hotel is equipped with a special light booth for body clock resetting: What if your only chance to take sunlight starts a few hours before or after the Deleter's recommendation? You might then wonder whether or not to do it. Here's how to find out: Turn the transparent FROM-map a little, until its arrow points at a number a few hours earlier or later than the best one indicated when your FROM-city closely overlay your TO-city. If your FROM-city is then only a couple time zones away from your TO-city, you may want to take that sunlight when you can. But if it is many time zones away you might be better off to avoid sunlight until best time tomorrow. Here is the Miami-Tokyo example restated to include such modification:
Rotate Miami on the transparent FROM map to nearly overlay Tokyo on the opaque TO map. The arrow says to start sunlight exposure at hour 01 (1 AM) on to your Miami- time wristwatch. That will be in Tokyo's late afternoon. If it is overcast then, and you have to start an hour later (2 AM by your Miami wristwatch) turn the arrow to 2 and see from the maps that you will be resetting your Miami body clock for places 2 time zones further to the west: Burma or Western Australia. (The arrow then indicates mid-afternoon in Burma, not in Tokyo). This is not too bad, so you might do it.
At any time when sunlight is available you might wonder whether or not to look at the bright scenery. Rotate the transparent map until the arrow points to the time now indicated on your FROM wristwatch. See where that puts your FROM city: if in a time zone far from your TO city, don't start sunlight then. For example if your plane from Miami stops in Hawaii, would it be good to take some sunlight there? The answer is still the same: only if your Miami wristwatch then says 1 AM will you reset to Tokyo time. (Even if it did, there is no sunlight: 1 AM Miami is 8 PM Honolulu, as you can see by counting the 5 time zones on the transparent map.) But suppose it says 16 (4 PM) in Miami. Rotate the arrow to 16 to see that such an exposure would reset Miami people to roughly Seattle time, 7 time zones ahead of Tokyo. (Once again, the arrow's NOON reading now means "in Seattle"). That 7 hour mistake is too much, so don't peer out from a porthole on the sunny side of the plane during refueling: go on to Tokyo without upsetting your body clock with sunlight, then start your exposure at Miami 1 AM as planned.
Here is another little refinement that you might want to try. We quietly supposed that your personal body clock is the same as that of anyone else in the same time zone. That is probably not so. First light for you might be hours earlier or later than someone else's, and the same for your personal 'sunset', when you habitually last expose yourself to sufficient daylight brightness to affect your clock. So you might effectively be in a different time zone! "No matter," you say, "my habits are the same in Singapore, so I still want to change by the same number of hours as anyone else on this flight." True. But your clock and hers are a couple hours apart, so when it comes time for exposure they will react somewhat differently. You might think this is a small correction and you might not want to bother with it. But if you are doing a long trip and needing a big phase shift, it so happens that this can be obtained only in a part of the clock's cycle where not only is the response to light big, but it is also very sensitive to timing. If you want to attempt this refinement, try this: If you are an 'early bird' by an hour or two relative to the average person, start your exposure an hour or two before the Jet-Lag Deleter's recommendation, and if you are a 'night-owl' by as much, start it that much later.
In all of this calculating, further refinements are possible but I think they rapidly become smaller and less reliable. Corrections by an hour or so can be made by additionally inputting season and latitude, because strictly speaking the JetLag Deleter as presented here is only for use near the equator and/or around the equinoxes (March or September 21) when the North and South Poles are on the globe's moving ring of sunrises and sunsets. But such possible corrections are still within the error margins of biological factors and of the uncontrollable light intensity and duration. So this calculator just embodies the key principle and should be regarded as an attempt, better than anything else we have seen, to harvest most value for least complexity in an imperfect world.
If brain clocks interest you, you are onto a rich topic. Lots of experiments and medical lore are colorfully illustrated in a Scientific American Library book (now out of print after 40,000, but available in libraries): The Timing of Biological Clocks, by A.T. Winfree, Scientific American Library (1986). An earlier and more technical book is The Clocks That Time Us, by M.C. Moore-Ede, F.M. Sulzman, and C.A.Fuller, Harvard Univ Press 1982. This "Jet-Lag Deleter"'s simple prescription is based on the universal schedule of body clock resetting discovered in animals (Winfree Ph.D. thesis, published in J.Theoretical Biology 28, 327-374 (1970) and summarized abstractly in Physics Today 28, 34-39 (1975). In 1989 application to humans was spot- checked clinically (Science 244, 1328; Nature 350, 59). Calculations refined to take account of season, latitude, brightness, and duration of exposure might differ by a few hours; in any case, people differ that much in their daily body rhythms.