16th Note Right Hand Lead - This means that you are doing each hand for the length of a 16th Note, which means that you will be alternating (or going back-and-forth between) your right and left hands. You lead with your right hand.

16th Note Left Hand Lead - This means that you are doing each hand for the length of a 16th Note, which means that you will be alternating (or going back-and-forth between) your left and right hands. You lead, or start, with your left hand.

8th Note Right Hand Lead - This means that you are doing each hand for the length of a 8th Note (which lasts 1/2 of a beat) and that you are leading with your right hand. 

8th Note Left Hand Lead - This means that you are doing each hand for the length of a 8th Note (which is 1/2 of a beat) and that you are leading with your left hand. 

Whole Note Right Hand Lead - This means that you are doing each hand for the length of a Whole Note (which lasts 4 beats) and that you are leading (or starting) with your right hand. Since a whole note lasts the whole bar, we only use our right hand for this one.

Whole Note Left Hand Lead - This means that you are doing each hand for the length of a Whole Note (which lasts 4 beats) and that you are leading  (or starting) with your left hand. Since a whole note lasts the whole bar, we only use our left hand for this one.

Half Note Right Hand Lead - This means that you are doing each hand for the length of a Half Note (which lasts 2 beats) and that you are leading (or starting) with your right hand. For the first half of the bar, we use our right hand, in the second half, we use our left hand.

Half Note Left Hand Lead - This means that you are doing each hand for the length of a Half Note (which lasts 2 beats) and that you are leading (or starting) with your left hand. For the first half of the bar, we use our left hand, in the second half, we use our right hand.

Quarter Note Right Hand Lead - This means that you are doing each hand for the length of a Quarter Note (which lasts 1 beat) and that you are leading (or starting) with your right hand. 

Quarter Note Left Hand Lead - This means that you are doing each hand for the length of a Quarter Note (which lasts 1 beat) and that you are leading (or starting) with your left hand.