I got approved for Medi-cal, what do I do now?

I am pregnant and got approved for medi-cal 4/30/26. It says my eligibility start date is 6/01/26. What does that mean? Does that mean I can't go to hospital before that?

Also I heard I will have a mail with health plan options. That will take another 2 weeks to come and does that mean I can only choose from those healthcare plans? I want to go to UCI for my prenatal care, giving birth, and postpartum. Can I just call them and make an appointment through just medi-cal?