You can find a representative screenshot at
http://halera.tumblr.com. Basically, you have to remember the flags at the top of the screen, and find them in the bunch below, on the next screen. Then repeat 10 times, before the clock runs out. In the first level, you start with just one flag to remember, and 4 in the bunch to select it from, and end up with 4 to remember, and 16 to select from.
That's probably not the best explanation for the game; I think it would probably be best if you could try it out for yourself. Thanks!
