Hey Jim, I've attached the first lyric from the song, and how the rhythm of the vocal compares with the strums.

The thing that is a bit complicated is that the third strum of every bar is a 16th note, while the vocal sticks to 8th notes. If you're having trouble with the timing, I would suggest leaving that quick 16th note strum out of your strumming, so that it will be a little easier to sync up the other strums with the natural pulse of the vocal.

I hope this helps, please let me know if there's anything else I can do!!
Mike