Alphaturian

Hi, Random noobi question! Is there ways to control set portions of the map? IE, have the centre of the map pre-created, something like writing in a specific landmass (like a volcano) in the centre, and then certain biome in the middle, that sort of control? Or not. My main aim will be to build a map that has a volcano full of dragons, surrounded by desert, and then the rest of eco systems around and water far out... So everything in one! Also, is there a main place where people are uploading their PGM's? Are these uploadable to the steam community yet?