Hello! Thanks for downloading my tileset. May I ask what program you're using these in? I'm mostly familiar with Unity and found that this tutorial helped me a great deal when I was starting out:

As for turning the 3D tilemap into 2D through Unity, I can't check it at the moment. I'm just guessing, but I figure rotating the tilemap should work(?) If I remember correctly, the difference between 3D and 2D in unity is how the camera is placed. So in theory it should work still.

I'll update you once I get the chance to check it out! Thanks again!