Hey, hope you're well!
1. When you get the attack drone roll a d4 this is how many fights it will support in. So for example if you roll a 3, for the next three fights, roll a D8 at the start of the fight and immediately deduct that HP from your enemy - the rest of the fight carrys on as normal.
2. Each combat round is just one roll which represents you both attacking each other. If you succeed the roll you hit the enemy, if you fail the enemy hits you.
Hope this helps :)
Aaron