My nearby reserve center didn't have a clue what to do for me, and I had no prior service to realize that often the YNs just need to be told what to do. Fortunately, there was another student prior line officer who helped a lot. You should have no problem as you've done all this before. Anyway, I went to the center, got my orders stamped, left, came back 45 days later and did the same thing. 30 minutes on each end after the inital flail. You'll likely need to do partial school orders again during 3rd and 4th year as well, since student rotations are 30 days and the AT is 45. I always just did the 2 weeks extra as school orders, though looking back I culd have made better use of the time, probably.
Bottom line, it shouldn't be a big deal or time waste.