I'd pick up the Defensive Security Handbook at a start.
Templates for policies & procedures can be found at SANS.
I'd also familiarize yourself with some of the security frameworks- ISO 27001/2, NIST 800-53, NIST CSF to see what you may want to consider aligning with.
I have to recommend Amanda Berlin and Lee Brotherston's book : https://www.amazon.com/Defensive-Security-Handbook-Practices-Infrastructure/dp/1491960388
Look at the SANS website. They have some downloadable Word docs with basic questions. Other Google searches for 'audit' checklists will bring up some others.
From the audits that I've been part of, you need to focus on these key areas:
Also, take a look at this book. It helped me get a security program started, from the ground up. https://www.amazon.com/Defensive-Security-Handbook-Practices-Infrastructure/dp/1491960388/ref=sr_1_15?keywords=building+a+network+security&qid=1566233244&s=gateway&sr=8-15