Assumption:
EmuNand has installed already
1. Downgrade mset using GW as you have OoT entrypoint.
2. Install bluecardfix.cia using GW sysnand GW mode / DevMenu
3. Install ReiNand Rop (rnInstall.nds) using Blue card ds flashcart from ReiNand V2 on Rei Pastebin
4. Copy all files and folder from ReiNand V2 to the root of 3DS's mSD (rei folder, ReiNand.dat)
5. DS Profile > ReiNand EmuNand