There are basically two ways of doing procedural content creation, the first one is to create all from scratch even the geometry and the second is to use pre-made content and spawn it in the map applying procedural algorithms.
Thank’s for the answer, i want to use only blueprint and i have look “3:30pm ET - Training - Procedural Room Generation - Live from HQ” but i don’t know how i cam make a map a big map with some layer.
There are many ways on doing layers, you can do it just block-based like in minecraft or really creating different types of ‘tiles’ that represent water, sand, grass, etc.
This wiki has a lot of information about most of the techniques used, you can implement them in blueprint.