there are 2 way to do post-bacc...
1) informal, meaning you just entrol into any university and just take courses, you plan your schedule, you do everything (this is what I did)
2) apply and get accepted into special post-bacc programs designed for pre-med / pre-dental students. My underestanding this, these formal pose-bacc courses start you from scratch (100 level biologies, 100 level general chemistries, your 2 orgo courses and all thier labs)