MadDog, it very much depends on where you end up. Working only Monday to Friday is very unlikely, as is being able to choose your shifts. You'll be assigned a line on the roster & progress though it, repeating the roster typically over a 6 or 8 week period.
You may not start off working doggo shifts (2300-0600 plus or minus) if you don't have the necessary ratings. In which case you might work a couple of afternoon shifts followed by a couple of morning shifts. Otherwise a typical cycle is 1500-2300, 1200-2000, 0600-1300, 2300-0600, off, off. Rinse & repeat with the odd block of afternoons/mornings thrown in.
Each group of sectors has different requirements due to traffic patterns & rosters are written to account for this.