What you need is a book on Music Theory. A good one I thought was very good was "The Complete Idiot's Guide to Music Theory". I assume that you would have already signed up for Full Access by now if you had the means because of course that would be better than a book.. but I notice you asking a lot of related questions one after the other.. If you had a little better understand of the basics of Music Theory, you might be able to make all of these connections yourself.

With your current issue.. the chords, the melody, the rhythm, the timing.. they are all your own personal choice.. if it doesn't sound "right" to you then you need to change something. If the rhythm part is the least important to you, then try to find a chord progression and rhythm pattern that makes it just as important as the rest of the pieces. It might be as simple as a I IV V progression but it could be anything. That music theory book teaches all sorts of useful things, including a chart on all the "commonly used" progressions. It also teaches things about chord leading and other junk that you will find useful along the way.