Dribble/Fumble

[JLC]

Just looking for feedback here. I am not an official. I coach 9th grade boys, and in that process, attempt to teach them the rules. I buy rules and case book every year (and actually read them), and follow this board. Have learned a lot, and have good discussions with friends who are officials. Anyway, is there any "rule of thumb" on what you would consider a fumble v. a dribble? Seems this is an area that is really difficult, especially the case where a pass "bounces" off a player's hand(s) to the floor, he picks it up, then starts to dribble. Does the player have control if he seems to direct the pass to the floor? A lot of judgment involved I know. What do you look for in cases like this?? Thanks