The last time I was in a Barnes & Noble, they had a lady at the Nook counter who was teaching new Nookers how to use it, so you should be able to get them to show you how to do stuff and maybe set it up if it needs setting up. (not sure if they send Nooks already registered in with your account with the store like Amazon does with the Kindle)

Dont forget to get a cover for your Nook along with the screen protector. Nooks and Kindles have delicate screens (dont believe those Kindle commercials where people are running and jumping over boulders while reading)

Half the fun of having my Kindle is accessorizing it. I just buy covers for it occasionally, but some of my online Kindle friends have bought "skins" (plastic decorative covers for the body of the Kindle) and I know they make skins for the Nook too. Makes it so you can personalize your ereader a little bit.