Originally Posted by AuxPumplow

You are going to have an FOM that's particular for your airline (procedures, policies, rules, regs). Usually you get about a week or so for that during indoctrination.
You wanna know fundamental things. How jet engines work, basic electrical systems knowledge, and of course instrument procedures.

If you know Absolutely nothing about aircraft more complex than a Cessna 172 (turbines, electrical, pressurization, hydraulics), or have weak instrument skills you're gonna struggle.