I have never taken birthcontrol pills, my question is when should i take the first tri-sprintec tablet? and how long do i have to wait so it works

Sunday is the norm..: You can technically start anytime and your cycle will adjust to the medication. But most women find it easiest to start on a Sunday, the way the packs come labeled. You should take it the first Sunday after the start of your period. You should use a second form of birth control for 2 weeks. It may take several months before your cycle is regulated on the pill.