One Night at the Storage

You've been hired to keep guard of a storage facility overnight with safely kept items. It's the only job in town and it gifts money per hour.  
The task is simple, check every now and then for any unusual things happening. Close your office doors in case of a threat, check the monitors for wherever they lurk.  
The power is limited on nights, the owner is a pretty cheap guy. And a mysterious book is left for you on your desk behind you. Maybe it could be helpful?

Backstory:
Walking around town, poor and in need of a job. You're out to prove your brother you could get a bit of cash. You stumble upon a paper sheet nailed to a pole. 
On the bottom read, "for hire," and the location. So you apply over to the location. Without any of the required experience you need to be hired, you deal with the owner to give all your savings to be hired.
Later that day, you've been informed by the owner to watch out for intruders and knock them out on sight.  
You walk in the office. Your shift begins, but a sudden call interrupts you.