its just trial and error, i haven't a clue if i need to head north, south, east or west. I just look at the closest pokemon on the list and look for the leaves that pops up and go towards that direction and see if it matches whats indicated.

The thing I learned that's been most helpful is the list from top left to bottom right tells you which Pokemon is closest to you. So if you have multiple Pokemon with the same distance you walk until the one you want moves closer to the top left. Then you know you're truly heading in the right direction. It even updates before the footprints do.