Go to your team homepage, there you will see a realtime tracker that is counting down to draft day. Within that box you will see "Pre-draft Player rankings," click the link.
On the next page, click the yellow link titled, "Edit My Rankings."
From here you manually input players into your draft box on the right, or in the exempt box on the left. The center box is the Yahoo Rankings box where all NHL players are located.
Though personally being that this is your first crack at NHL fantasy hockey, I would go with the Yahoo rankings as they aren't too bad. The draft will occur, and although you may not be present the autodraft will happen regardless.