It's pretty easy;

Download wallet from their website, LLD + LLD Database, Install wallet, then close it,
drag and drop database into nexus appdata / roaming folder.
Also in the appdata / roaming folder, create text file, write this:

llpallowip=127.0.0.1:9325
mining=1
unified=1

save as nexus.conf (make sure it's .conf not .conf.txt)
open wallet back up and let it catch up sync'ing the blockchain.
Wait until there is a green check at the bottom right

Miner is an SK miner mod, works great
https://www.dropbox.com/s/epbqsmcq47e4v62/SKMinerV1.0.zip?dl=0

Edit the bat file and change the "1" to however many cards you have on your rig.

Once you see the green check, run the miner.

Hit blocks.

I would recommend checking this website: https://nxsorbitalscan.com/ a couple times a day to make sure your miner is on the same block, sometimes I have to reset the wallet and miner every 3-4 days.