When I installed d2x, here's what I did:
1. Put wad files in a "wad" folder of my SD card (this doesn't really matter but I'm just saying).
2. Load a wad installer (like multi mod manager) and load into IOS 249 (again, others may work but I'm just saying what I did).
3. Click on install wad and install every wad you got in the d2x pack.
Let me know if you have any problems, I'll be glad to help