KPI = Key Performance Indicators. We measure what's important to us. Ask how your performance will be measured. Ask how your boss's performance is measured. Help him achieve these goals.
Sometimes, it's squishy. That's bad. Try to make it more specific, more measureable, by building in specific milestones that get you closer to whatever squishy thing was poorly defined. Sometimes, they move the goal posts. That can be bad. Document what they asked you to do at a point in time, so when it changes, you can have a new conversation about how to get from wherever you are, to where they want you to go.
Recommend you read the excellent business fable, _Three Signs of a Miserable Job_ by Patrick Lencioni.
Congrats on the new job. Since you mentioned audit readiness, I would also ask the question, "Was an audit performed recently? May I see it, along with our response to the audit?" If there wasn't an audit recently, ask, "What do we expect the auditor to ask?" Auditors typically look for a defined process for how work is done, and evidence that the process is being followed. That is a good place to start.