How long is a piece of string.....................
Seriously though, anything up to two weeks, some people get a start date the day they are told they're in the pool others have to wait a bit longer....
Simply depends on what courses are sheduled I guess i.e. only 777 and no ZFT you'll need to wait until the next Airbus or 757 course gets scheduled in........
Good luck with the sim!
BADEPS