They will ask you a lot of basic questions pertaining to the role of a security guard. If you've done it in the past it'll be very easy. If you have not, just use common sense, really. During your initial phone screen interview, make sure you ask them what costs are involved with accepting this position.
There are high costs (about $130 total) that they did not tell me prior to onboarding paperwork. Aside from these upfront costs, you will have to repay the licensing fee annually. This is where I decided to move on from accepting the role as I have never had to pay fees when employed by a company. There may be other costs that I had not yet discovered. Make sure you ask this specific question otherwise they will not inform you of it until, literally, the very last minute. I received an email from them while I was sitting in their lobby 5 minutes prior to starting my onboarding paperwork. There is absolutely no excuse for them to have not shared this information with me in the initial interview.
Aside from this issue, the people there are friendly which made dealing with this much easier. It definitely was a disappointment. Had they stated the costs involved with this position in the original job posting (Craig's List, Indeed and their website) I would not have applied.