This is a complicated, multi-faceted question that you aren't going to get one simple answer to. You need to research how procedural generation is done as there are many approaches.
For biomes/minecraft style generation here is a good breakdown of the concepts: procjam.com/tutorials/en/ooze
While it's not biome based, Rex does provide some dungeon generation:
You may want to consider Seed generation as well, that tutorial link above covers it a bit, just know that there are Construct2 plugins that can "freeze" your seed so that you always generate the same terrain.
You'll also need to look into how to store the terrain your generator built, probably by writing to an Array object.