Help with userform (trying to read data from table into combo list)

I am hopelessly trying to get a simple combo list to work.

The table is on Sheet 2. User must be able to pick width first, then depth combo list should pop up and then once depth is chosen, the corresponding part number should pop up in the same window.

If someone could help me out with this code, I'd really appreciate it. I have about 20 sheets with as many tables that need to be managed on individual userforms and then finally linked with a main page userform. That I think I've figured out but I can't get these combo boxes to work.