Okay ... there's a lot of ground to cover. So, first tings first.
Basics of the game's combat:
1. You can click on an attack, and then mouse over to your target, to see the chances to hit. And while you're doing that, see if there is a green or red arc around the circle. A green arc means you have Advantage (more on this below), or Disadvantage. You want to have Advantage when attacking.
2. What are Advantage and Disadvantage?
a. Advantage means the game rolls 2 dice at the same and the higher result is used. For a simple example, say the target has an AC of 15. The game rolls two dice at once with the results of 4 and 17. 17 is used, and you hit the target with your attack.
b. Disadvantage means the game rolls 2 dice at the same time and the lower result is used. In the above example, 4 is used because you have Disadvantage, so you miss the target.
Therefore, you do not want to be put in a situation where you have to attack with Disadvantage, instead, you want to attack with Advantage.
How to get Advantage
Attacking from stealth (applies to both melee and ranged attacks)
Attacking from high ground (applies only to ranged, mostly)
Attacking from behind (applies only to melee, mostly)
How to get Disadvantage
Attacking from low ground.
Attacking from high ground as ranged but target is prone.
Attacking in dim light without Darkvision.
Attacking with ranged weapon or ranged spells while an enemy is near you.
Thus concludes Larian combat 101.
