Nice start, keep going.
The official GraalEditor. When you start the Graal client for PC, then log in there, start (bottom left) > Install Packages > Developer Tools > Level Editor.
You can get the development stuff (tileset, few images etc) by logging on Era (the PC version) > start (bottom left again, if you cant see it then click on the arrow on the bottom right showing to the left) > Install Packages > Era Development Kit (maybe also Essential Graphics, not sure)