I have some questions about opening a security business.?

There are some challenges in opening the security business.
IF you please clarify either you want to sale the security devices or want to provide security services ? If you want to provide security services to the people just you need security persons and weapons and their licenses. Its a kind of a good investment in terms of purchasing weapons. It may be simple to open but difficult to run. As far as companies are concern who want security you can do advertisement of your business via proper channel like in local TV medium news paper .. or internet .