please someone help me understand how to play rumble...i am begging for help

i want to understand how to play rumble because i want to make awesome ults with him.....i can't do laning phase.....no matter who i go against i cant do anything....i try to attack with my Q and they turn and just half health me....i can't hit E because they are always behind minions....please..........i don't understand how i do so little damage and they can just turn and do half my max health in an instant while im doing nothing...please...im begging you...someone please help me understnad how to play this champ