For now, given that you are just starting out, don't worry about building chords with the left hand. Use the left hand as bass, to reinforce the chords you form with your right hand. You use the root note of the chord as your bass in the left hand, playing that root either with just the left hand pinky finger, or as an octave (which sounds fuller) using pinky and thumb.

So if you're playing say a C Chord in the right hand (notes...C, E and G) you want to play an octave of C notes at the same time, with the left hand.

A couple of good practise exercises for the left hand would be to take that octave position and practise playing a C scale (and other scales) using the octave method. Then try ''walking'' the octaves...which means, pinky down first, then thumb, then pinky down on next note in the scale, then thumb....This is a fundamental method for getting a ''boogie woogie'' feel in the left hand...once you have it down and speed it up and swing it a little.

I am sure Mel Bay has tonnes of books on piano instruction...I don't really know what book to suggest as it's been 40 years since I started. Try my suggestions though. I think they will help and get you started in a good direction. (Don't worry about forming chord shapes in the left hand for now; this comes later on when you no longer have to think about what your right hand is doing.)