NPCs collide with collider but player does not

I want to put in a box collider in an area.

have NPCs wander around in that area and collide with the box

but not have the player collide with it. how do you do that? is it layering?

I added an image to illistrate my question. I want the NPC to wander around inside the collider and not leave the area.. I then want my player to be able to move in and out of it. oh, forgot, this is also a trigger for spawning in the same area.

sorry bout that last part.