Various landmarks are 'pokestops', where you can get pokeballs and other items. Some of those places are gyms, where you can pit your pokemon against others.
The pokemon themselves are spawned from random spots on the map and wander around, if you're in the area and have the app open you'll see it and can capture it by throwing pokeballs at it. There's a kind of wonky proximity indicator for nearby pokemon, and they're shown on the map by the random appearance of rustling grass.
The pokemon themselves are spawned from random spots on the map and wander around, if you're in the area and have the app open you'll see it and can capture it by throwing pokeballs at it. There's a kind of wonky proximity indicator for nearby pokemon, and they're shown on the map by the random appearance of rustling grass.