2D Terrain Collison

I watched a tutorial to make procedural terrain generation with noise and that worked, thank god, but I need a collider on the terrain so that my player doesn't fall through it. Obviously adding a collision box won't work because I can't shape it around the terrain, so what am I supposed to do?

Also I'm new-ish with coding so try not to force anything advance on me without explaining.

 

So your terrain generation isn't using cube-like sprites? If they aren't a standard geometrical shape, you can probably just use one or a few edge colliders2D and you can bend and stretch them as you need. Note, dont try to enclose an edge collider, just think of it as a 2D line that can bend.

If they are just cubes, then just throw a box collider2D on the prefab.

 

use the terrain generation code to generate the colliders