How to make textures that fit a custom model block?

I've been messing around for a few hours trying to make a slab, and after looking around I figured out how to make the block model. But I can't seem to puzzle out how to make a texture to fit the block. At the moment it's just an invisible block but only half the height of a block (like a slab)... Anyone know how to make block textures for custom blocks (at the moment specifically slabs)? Sorry if this is something actually easy, I'm sort of new to modding with MCreator.

The second post (the one right below this from me) isn't supposed to be there, pay it no mind lol