Not sure what game modes will be on this time, they may tweet before hand, like last clan war, but this link shows times for both divisions
If your in the bronze through platinum division that clan war starts on the 2nd. At 12 pm pst and you will have to wait for it to start to see the game modes.
if your in diamond that clan war starts in the 4 th and the time depends on which time slot your clan leader selected.
So unless your in a time zone that has 12 pm pst on the 4-2 convert to a time on the third you have the wrong start date.