herewego

Understanding reserve is something that takes months to understand. It is only something that can be learned from living the dream, which with reserve can quickly turn into a nightmare.
The basic info you'll get from your check airman and in discussions during breaks that you initiate, but nothing is formally taught.
Know that your reserve shift (RAP or Reserve Availability Period) is actually a time you must be able to answer the phone or acknowledge a call out within 10 minutes, to be at the airplane within two hours (short call). It is not the only time you may be required to fly. you can be on a 5AM-5PM call out and get called to fly until 11PM on day 1 then return to base at 2AM on the morning after your last RAP. They can not force you to be to the plane in less than 2 hours (short call), but will try to convince you to do so. NEVER say you will be there in less than two hours, Let me repeat, NEVER say you will be there in less than two hours. you can say "I'll get there as soon as possible, but I need my full two hours."
An AM reserve shift does not mean you will fly only day legs, and a PM reserve can be called at 8:59PM to show at 7AM the next morning to do day flying.
There is much more in the Reserve Survival Guide that is in the SAPA Section on the company issued iPad you will get in training. Don't worry about that until you are through with IOE. Sure you can peruse it when you're bored waiting for IOE, but it's not testable, it's not relevant to operating the plane, and it should be the last thing to waste brain cells on until you're done with training.