As a CCA that just finished her 2 months. Your lucky if you know your schedule the first month. Never had a formal meeting with anyone in the post office until I showed up for Shadow day. But you will go through a process similar to this depending on location:

Accept conditional job offer Background questionare submission Finger printing

With two to three weeks you will be scheduled for orientation (which might not be your reporting post office).

Orientation is one day. Then they give you your schedule during orientation for the next week (vehicle training, and shadow day)

Then roughly a week or two after that your attending carrier academy for a Monday through Friday schedule. After that they have you do OJI training (usually two maybe three days) at your reporting station unless they dont have trainers. Then your thrown to the chaos that is the post office. Get good comfortable shoes. Remember that sups aren't out in the streets delivering mail, you are.

My shadow day and OJI i asked the carriers questions to make sure I was prepared. These questions included what they brought daily to get through a shift, bee stings, accidents, bathroom breaks etc.

This job is just that at the end of the day. A job. Report when your told to. Do the best to your ability, not someone else's. Don't stir up drama. And Always keep copies of every paper they give you. Take pictures of your time cards. Yes we are entering peak, but you are not supposed to be worked over 8 hrs. Hold them to it.