Noob in need of handholding for CFW install

I must be completely hopeless because I've tried to do this twice already and I'm stuck. I have a N3DS XL on 9.0.0-20U and I've been trying to setup Reinand CFW. The first time I got it to the point where I would unlink the EmuNAND from SysNAND but then my Devmenu disappeared. Since I downgraded my MSET and didn't have a microSD card adapter I totally screwed myself and didn't have a way to access the files on my card.

My new microSD card has arrived WITH an SD adapter, but now I'm stuck...

Noob in need of handholding for CFW install