the game uses an auto-battler, so fights play out by themselves and the exclamation marks are enemy locations. So your job is balancing your health and running around being in battle collecting wise amounts of enemies at the same time to get better loot and still survive. And run to health stations when needed. The battle time is also a great time to get more XP since you cannot get bored while being in battle. That, i think is the core mechanics of act one of the game.