No problem there will be plenty of tours available and you will get a list off PNO before you leave home to book if you wish. It is easier to go on the tours if you are in the fiord area as the towns with the exception of Bergen are well away from the best areas. Msake sure you are up early to see the views going into the Firods as it can take up to four hours to complete the trip in. Our favourite is the Oslo fiord.
Bergen & stavanger yoy can do by yourself quite easily flaam i suggest that you walk from the ship 5 min walk to the railway get the train up into the hills & back really good view.