Banjola and attempt at singing--ok if you laugh

I thought I’d try to learn a few chords and try to sing along. I found I’ve been concentrating so hard just to play, that singing along was more than I could handle.  Chords are also challenging after fretting mainly single notes at a time. This song has simple chords and needs limited singing range so it’s good for a first attempt. And, it is such a fun song so please laugh with me.

Unfortunately, I’m not really sure how to add the 5^th string so that is my question. 

http://youtu.be/kj9XwnG7dAM