You'll start with only your trusty Cael Hammer. Follow the path, smashing through debris and getting used to the controls. Rucks will begin his narration, setting the scene. Your first enemies will be Squirts, small, easily defeated creatures. Use your Cael Hammer's primary attack to dispatch them. dodge roll (Spacebar) to avoid their charges.
As you progress, you'll encounter your first weapon, the Breaker's Bow. Pick it up and equip it as your secondary weapon. Practice switching between the Cael Hammer and the Breaker's Bow (Q key). The bow is excellent for ranged combat and picking off enemies from a distance. You'll also find your first Health Tonic. Use it when your health is low (default key is usually '1' or '2' depending on your setup, check your keybinds). Continue following the path, defeating more Squirts and learning the ropes of combat.