IThere isn't a more classic uke song than this and I can't quite understand why people don't play it in the original key as it works pretty well . The hard part in a sense is deciding which vocal line to take so I've shown you the main 3 lines here marked X Y Z . The Y line I think is the melody which starts on a B.
Things to do with this song include grooving at the start in E7 and playing the Bassline part. I deally this is a song for a group of you but it's still fun on your own. Enjoy !