It's really easy, the three chords after each line of the verse are just
an A shaped bar chord being slid up the neck.
Joy to the World (Three Dog Night)
Jeremiah was a bullfrog
A very good friend of mine.
I never understood a single word he said
But I helped him to drink his wine
Yes he always had some mighty fine wine
Chorus
Singing Joy to the World
To all the boys and girls
Joy to the fishes in the deep blue sea
Joy to you and me.