Right hand taps your head and don't stop, left hand rubs your belly while still tapping your head. Now with the hand rubbing your belly tap your first finger while still rubbing. So you have 3 things going on at the same time.
Then try it with your 2nd, 3rd and forth.
Now reverse that, left hand taps belly while right rubs head and taps fingers.
It's kind of like a drummer playing different rythems with each limb. It's hard a first to get your right hand to beat the hi-hat in a different timing than you right foot is thumping the bass.
With time and effort your body will learn.
