how do i make it so the legs on my robot dont tear up the terrain so much?

I think people would be able to help you more if they had pictures and a piece of code to work from. If I base myself off previous encounters of the shitty crab walkpaths, I think the problem is hardcoded.

Decrease the push force a little, that's what sends it through the terrain.

Or you can make it's foot's atomgroup wider. That's pretty complex tho'. Still not too hard, if you're capable of offsetting.

ok the push force fixed it. Another question real quick, how can i make the legs longer?

That needs some fiddling with the walkpaths. Easiest way to do it would be by increasing the StartOffset of it's walkpath and standpaths. There's a separate walkpath and a standpath for it's left and right legs, so you need to change the StartOffset for 4 paths.