Well, basically if you want to use sub-d’s, all you need to do is press the “SubSurf” button in the Edit Buttons window.
For a basic example, do:
- Press “SubSurf” button
- Increase or decrese “Subdiv” to your liking
See what that does and you will see what Sub-d modelling does. One key thing to remember when modelling in sub-d’s is to always use square, or quad, faces. Triangular meshes are not handled very well by sub-d.
Hope that helps. If you need some more info, then just post a reply and I’ll see what I, or others, can do for you.