You sculpt using sculpting brushes. You select sculpting brushes from the Tool Trays located at the bottom of the 3D view. Read on to find out more about the Mudbox's tools.
Intro to the Rock wall sculpting, retopologizing and texturing upcoming tutorials.
This tutorial uses Autodesk Maya, Mudbox, Adobe Photoshop and Xnormal, be aware that these probably won't be the most current versions for you but they're what I have so deal with it.
This is a step by step tutorial illustrating the workflow between Maya and Mudbox
1-Mesh preparation
2-UV alignment
3-OBJ Export
4-Sculpting tools
5-Displacement Map Extraction
6-Mental ray setup
7-Approximation editor
8-Render