You won't have any accrued vacation when you start. The vacation "year" goes from April-March, with bidding in January. How much vacation you get on that first bid just depends on when you start. Also note that you can't split up any vacation that is less than a full week, so if you have say 10 days accrued, you'll have to take that in 1 single 10 day stretch. You can't take a 7 day week and put the other 3 days on another week in the year.