Is it possible to make alien world tilesets?

What I mean is: Is it possible to make a completely new alien world - from scratch - with a matching tileset? Or do you have to use existing tiles to make the new alien terrain tiles? If so, how would i go about doing it?
Thanks for any help anyone gives me.

You can create and import as many custom tiles as you want to, the way you apply them is by overriding already existing tiles, so yes, you can create your "alien world".

The way you create tilesets is the same way as you create skins. If you don't know how to do that then check out our tutorials section for some starters guides.

Also, remember that tiles layer from right to left. The rightmost tile is always applied 'over' any tile to the left when they border each other.