Follow the guide, and READ and RE-READ the guide before doing anything.
Also - basically the process is this: downgrade your system to 9.2.20 firmware (already done), create a copy of your home menu called an EMU/REDNAND, format your RedNAND twice, downgrade your RedNAND to 2.1 firmware software, use a program to get your system specific files, flash your system firmware back onto it, and install the system specific files and then configure your 3DS cfw to your liking.