Tricare questions

Hello ladies I am soo confused about the different plans tricare has. My husband is in the Army and I would like someone to kind of explain it to me. Like do you get to pick your plan. Can you find other doctors who are off post who take tricare. My husband will be deployed when I have the baby so I really don’t want to have the baby on post I would rather have the baby closer to my family. Can someone please help I am new to this. (We just got married and are going through the paperwork this week.)