Act 5
.. I recommend following this skill tree path which was explicitly designed to make the gaming experience as pleasant as possible for new players. That being said, it focuses more on survivability and comfort than damage since these are way more important at the beginning, but the guide will elaborate on options to adjust the skill tree in order to be more damage centric for the endgame later.
This is optional, but adds an additional defensive layer since Granite Flasks provide additional armour (which scales with Determination). You get this as a quest reward for completing the quest The Key to Freedom.