The "I've never used one before" and the "disc changing/type of" statements.
Please, don't take offense, everyone has to learn sometime about using a machine unfamiliar to them.
It would probably be best to have someone there, who has used one before to show you what to look out for.
But other than that you're doing the next best thing and as you say, asking here.
The manual is also an invaluable source of info, even further searches on the web and don't forget youtube, there is bound to be some stuff there, good machine use and bad/dangerous use.
As said, no offense meant or anything like that. Just know that these machines can be very unkind to the operator, even experienced operators.