I don't have an idea of which bracket will go first each day, but according to my TV listings site Saturday games will be at 4:30pm and 7pm EST, and Sunday games will go at 2:30pm and 5pm EST. I expect this is pretty close to correct (CBS does not like to go late on Sunday's so as to allow 60 Minutes to air on-time in the East, but does like to have an evening matchup on Saturday). Actual tip-offs are probably all about 10-20 mins later than stated starting times.