The Mesh Edit tab contains several tools for, in general terms, adding geometry to your mesh to go on adding more detail.
Let me show you the most interesting and useful tools you will find here:
Slicing a mesh can be a good method of defining more interesting shapes. Let's take a look at how to use this tool.
The following screenshot shows the use of the Curve Slice tool. As you can see, you can make cuts with curvy shapes:
Viewing your mesh from a non-perspective view (better for this tool), start drawing a curve by placing points. That curve will be the final shape of the cut. Once you have it the way you want it, drop the tool and you will see the mesh is cut to that shape.
This second screenshot shows the use of the Loop Slice tool. This tool makes a slice call across a loop of polygons. The easiest use would be selecting an edge to cut across it. When you click on the tool, a slice will be generated across the entire loop corresponding to that...