Quartermaster Mathorn:
Before you only showed as much Death Knight power as was necessary for the training. Now it's time to show that we're not rookies here.
First press Tab or Alt + V to open your Inventory. Equip the weapons and armor you need if you haven't done it already.
You can open the Skill List by pressing Alt + K. If you changed class, you will see new skills that you can learn here as well. To learn skills you need to spend a specific amount of SP. Sometimes you will also need Spellbooks and Amulets.
I would also suggest you get the hang of Automatic Hunting. If you know what it is and how it works, however, you can skip this part.
Ask about Automatic Hunting "Let's skip it".