The lever for the door can only be opened from the other side, so you can not skip part of the catacombs. Pick up the teleporter stone (drag and drop into inventory) and use it to return to the first (or use the teleporter pad), then enter the catacombs and make your way down.

The warrior is the easiest class to play, with swords being the most plentiful high quality weapon type. See differences between classes.