How to put a texture/material on target layers?

I am new to UE4 so I just wanted to ask how to fill out ‘Target layers’ on the bottom of the ‘paint’ section of the landscape editor so that I am able to paint my terrain. Every tutorial I’ve seen involves the person making their own material using blueprints, but do you really have to do this to get a material into target layers? Can’t you just use a pre-made one? Anyway, any answers are appreciated. Thank you.

It’s all handled through a terrain material, yeah, I know, sick ■■■■, really makes you jump through hoops here…