Rooting the classic is a bit tricky. And yes the information is fairly fractured and especially hard to follow for the newer nooks. The thread in there about rooting SN 10101 nook's is probably the most comprehensive all in one source:
https://www.mobileread.com/forums/sho...d.php?t=121655
And even that is somewhat hard to follow.
Basically though the procedure is to find a way to configure your network so the DNS for the update server resolves to a site hosting the hack instead of B&N's real servers. Then you just let the nook update and it will hack itself. (Of course it's a bit tricky even then since getting ADB up and going isn't always smooth.) If you use one of the installer packages with the root then it will auto-install the nook market which will let you install trook really easily.
But - rooting the classic really isn't for the faint of heart right now. Even once it's hacked there are some things that needs to be tweaked through ADB to keep the battery life from being affected and keep it from doing B&N updates while not loosing it's registration.
Best advice I can give is to spend a week or so reading all the info you can about rooting and the various issues involved before jumping in.