You can only bid for schedules in your assigned base. That being said once you are a lineholder you may be able to pick up open trips in other bases, but you will always bid your monthly schedule in your base.

Reserve pilots get 11 days off per month. They are on duty at least 3 days in a row and no more than 6. There is short call and ready reserve. Short call is a 90 minute callout and comes in 12 hour shifts (4am-4pm or 12pm-12am). Ready reserve usually comes in 8 hour shifts and you have to sit at the airport. You cannot pick up flying on your days off. You cannot pick up open flying while on duty, it has to be assigned to you by the schedulers. You will be flown as a "call me first" reserve pilot until you have 100 hours in the airplane, so you may fly more at the beginning. After that first 100 hours, it all depends. Some days/weeks you will be super busy and fly a lot. Others you will sit around all week and go home without having flown at all.