When first starting out in skydiving, all the gear and options can feel very overwhelming. 

As a student, you get a crash course in how it works by watching someone explain it in a time sensitive environment. Full understanding is extremely unrealistic.   

When going through AFF you are taught how to Gear Check and make sure the gear is in jumpable configuration, but you have yet to (more than likely) have seen the inside of the reserve tray, the assembly of the AAD or how a soft link works. 

It is hard to trust what you don't fully understand.