It's only a 5 minute walk from the bus station to the Morning Sun Hotel.  As you can see from the map, after you get off the bus you keep walking in the same direction as the bus (about 1 minute) and turn left at the first street you get to. This is the main shopping street in Yangshuo and it is parallel to West Street, the main tourist street.  Walk about 2-3 minutes until you see the super market on your left.  Turn right and walk one more minute to the Morning Sun Hotel on your left.