Watch the Riverside: Rhythm 1 online guitar lesson by Andy Aledort from Jam Night Vol. 1
The verse and solo sections of "Down By the River" are simply two-chord vamps, Em7-A7, and in this example, I lay down what I would consider a primary rhythm part, one that is easy to play and sing over simultaneously; it also lays down a solid foundation for a secondary rhythm part. Keep in mind that this is a big part of what this "Jam Night!" series is about: how to suss out whether to play a primary or a supporting role when jamming with other people.