Medicare & Medicaid

I recently was awarded SSDI and I have Medicare as primary and Medicaid automatically became my secondary. I received a letter stating that due to my income my Medicaid will pay for my Medicare and will also offer better help and cover some of the other coverages. The main issue I’m having is that sometimes Medicare doesn’t cover the things that Medicaid covered and I don’t know how to use both insurances or now what my new Medicaid has to offer, the websites are very confusing and I’m not sure how to properly ask this question over the phone any advice from people who have both? How much for additional coverages if Medicaid is paying for them or where can I exactly get this information easier thank you!