Chapter 1: Journey Afoot
Objective: Defeat Sterling
Chapter 1 introduces you to the combat engine and your first four characters: Irving the warrior, Alden the mage, Maren the cleric and Garrick the ranger. Irving is the tank and will do decent damage with melee attacks while Alden and Garrick can attack at range without reprisal from melee opponents. Similarly melee attacks will not provoke a response from archers, but they will from mages. Maren rounds the group out with healing, but also can apply some damage in a pinch.
This leads to a fairly simple strategy for the chapter: soften up melee targets with Alden and Garrick and finish with Irving while Maren heals. Initiate on archers with Irving and Alden (at close range) and finish with Garrick if necessary.