Each Friday. The FAQ, the Game Rules and the "Center for rookies" forum area contains a lot of information worth reading before starting to make decisions about how you wish to manage your team.
It actually depends on where you live. It's each Friday (game time) at 04:00. But, for example in the EST time zone, the update translates to 10 PM on Thursdays in real time
Owner of the Orlando Gators FC Member GIAC
League 383-173 (TD Champs S17,S21,S22)
Regional Cup 223-25 (Cup Champs S14,S15,S17,S19,S20,S21)
AFLC 45-14 (Iron Bowl Champs S18,S22,S23)