If you aren't too familiar on how D&D works with its many incessant dice rolls, this should help you. If it doesn't then maybe you aren't the type to be playing D&D in the first place.
When you first enter combat, you both must roll 1d20 for initiative. Initiative determines who gets the first attack, and your Speed skill assists with this.
Let's just say you got initiative and attack. Then he attacks, and it goes back and forth.
1- Critical Fail, which gives the enemy a free hit along with his own attack
20- Critical Hit (The base damage, which can be upgraded, is 1.5x normal damage)
If you're not shit then the enemy and not you should be dead now.
When he's killed, roll 1d10 for XP. Now this is where it gets complicated: Ask the DM for the enemy's total HP if you haven't already memorized them. All digits save for the very last one on the right will be used as your amount of XP gained if you roll 1. However the entire enemy's HP number will be given if you roll 0. It works this way: Take the Angry Bat with 10HP. If I roll 1 then I get 1XP, which is terrible. However, if I roll 0 then I get 10XP. If this is confusing, ask your DM.
Now then, onto loot, which is what keeps some of you alive(other than welfare). You roll a single d20 for looting priveleges(However gold loot is done separately).
1- You get nothing somehow
2-5- Any visible weapons
6-12- Visible Weapons/Armor (Includes shields)
13-19- The above plus ammo, potions, food and hidden weapons
20- All of everything he ever owns
Now, if you've been paying attention you should have a good amount of shit in very short order.
Do 1d10 x 1d20 for looting bodies.
But, do 1d20 x 1d20 for looting chests.
Don't spend all your cash in one place.