General questions
The core idea here is that by clicking around on our map, you will be able to scan and discover monsters around you. To find monsters, you simply click around on the map and wait for it to complete scanning. By clicking around the map, you can also discover monsters that other trainers have discovered. That does imply that FastPokeMap is most effective when more people are using it in your area!
That's because our server is busy. We're a small team and we're working hard to increase our capacity to keep up with the amount of users on our site. Just keep trying until you get a scan through!
You might have enabled filtering of all monsters. The filter on this site removes monsters from the map, so if you enable it for everything, all monsters will be gone on the map. Check that first!

If that didn't work, we might be doing maintenance. Check our Twitter for updates.
Our maps are provided by a third party (we're very grateful to them). While they're great for some areas, other areas unfortunately haven't mapped out yet. This is definitely on our list of problems to solve. We're sorry for the meanwhile! One crude workaround is that you can try zooming out of the map.
Since the scan radius is so small, FastPokeMap is most effective when there are a lot of people using it. With more people scanning around, more monsters will be discovered. Central Park is a popular area, so lots of people are using it, which then means more monsters are discovered. You could try inviting your friends to use this site to scan around your town. The more the merrier!
Unfortunately, given how the API works, we can only get a general approximation but not the exact location of where a nearby monsters is. However, you can click on the monsters in the nearby box and narrow down the possible area it might be in.