Some setup codes are intended for TV or VCR or DVD, while others are combo codes for TV/VCR or TV/DVD.

Ultimately, you'll probably want to use the Combo setup codes-- 11922 for VCR/TV and 11948 for DVD/TV, but I recommend that you start using 10047 for the TV,  20522 for DVD, and 20060 for VCR functions.  Experiment with these and I think that you'll find that many functions are already in the remote.  No point in reinventing the wheel.

You really can't start doing much with the remote until you have the Combo unit running. Otherwise there is no feedback. In the meantime, you can download and install RMIR 2.00, and download a few upgrade files from the file section there.  I particularily recommend RCA TV.rmdu in the TV section, because it has a lot of functions.

You can get EFCs from these files.  In general RCA uses the same function numbers (OBCs in JP1-speak) for all components, but changes device numbers, so TV is 15, DVD is 5 and VCR is 14. 

Once you start using EFCs, I recommend that you use 11922 and 11948, and add EFCs to those.  When you find a function in an upgrade file you can transfer the info to an upgrade which uses the RCA Combo protocol.  Transfer the device number and OBC.  RM will then display the EFC, which you can enter into the remote.  I already linked to the 9XX instructions.

Another source of EFCs and setup codes is the Lookup Tool.  Search for Protocols, using RCA or RCA Combo, and of course the RS 15-134.  That will tell you which setup codes are in your remote, and the likely EFCs the correspond to a button.

Don't expect any support from Radio Shack or UEI.  Post questions at hifi-remote.com.