@yukinoh1989 I’m sure there area multiple ways to apply multiple colors to one object, but the one I’m most familiar is putting two material slots on the object, go to edit mode, select which faces you want to be one color, and then hit assign under the Material section. Repeat for other materials. But if there’s going to be a jagged edge, it might be better to control that through a texture map so you don’t have to worry about messing up your topology.
For the brushes, try hitting G on the keyboard and see if that brings up the Grab brush and not the Thumb brush.
