Better instructions are coming soon. For now:
The gear tables give you two sets of columns. On the left, you have a list of all gears on the bike, including duplicates and unusable gears. Duplicates are marked with an asterisk (*). On the right, the duplicates and unusable gears (such as inner chainring with the outer cog) are left as blank lines.
Within each set, there are four columns. The first gives the chainring number and cog number, counting from the inside. For example, "1-5" means the smallest chainring used with the fifth cog. This is what you see when you look down to find out what gear you're in. The next column gives the chainring teeth and cog teeth, such as 56/11 (if you're a monster sprinter!).
The last two columns are the most useful in evaluating a setup. The third gives the actual gear in inches, assuming a standard 27-inch (roughly 700C) wheel. (Other wheel sizes and metric gears are coming soon.) Finally, the last column gives the percentage difference from the gear just above. For example, if your first two gears are 1-1 and 1-2 (small chainring, first two cogs), the percentage listed by 1-2 might be 8.7; that means that when you shift from 1-1 to 1-2 you'll have to put out 8.7% more effort. In an ideal setup, all of these percentages would be exactly the same, and there would be no unusable gears.
The gear tables are displayed so that you can print the page and make a table to tape onto your handlebars. Just cut out the part with the numbers, leaving some extra paper at the bottom. We recommend using just the left set of four columns.
Then put a strip of clear packing tape (available from an office supply store) over the paper, leaving extra tape hanging over on all sides. Turn the paper over and put another strip of tape on the back side, so that the two pieces of tape stick together. This will make a waterproof seal. Trim the tape so that it is just a bit wider than the paper (1/8 inch, or 1-2 mm) on all sides.
Finally, wrap the strip of paper around your handlebars and tape it into a ring that is a bit bigger than the bars. Then you can easily move it around and read it while riding. You'll never again wonder, "What gear is just a little bit easier than what I'm riding right now?"