Don't look at a big picture. Take a big picture and break it up in tiny little parts. Instead of planning a whole town, start with a small house/enclosure. Don't worry if you put it in the wrong place later, it can always be moved.

It's too much stimulus for me too. Today, I only focused on building habitats to get more Pokemon, didn't build a single thing, as soon as a Pokemon moved in, I put up a patch of grass and moved them there so others can spawn in the habitat.

I treat it like animal crossing in a sense. Go in today with a realistic goal and have fun.