"Locking Through" for the first time or with an expensive boat can be very intimidating. If your boat is smaller than 80 ft. long x 27 ft. wide, you may use the easier small lock. You just tie up to the side walls that float up or down.
However on a busy summer weekend you might end up in the large lock with over 50 boats, incl. large ocean tugs and during low tide, so it is best to be well prepared...always carry a couple of 50 ft. lines aboard.