You’re aware that your visa will only be valid for 6 months from the date of the medical?
Not sure what info you need to prepare, but everything you need to know about what to take is on the usual website (https://travel.state.gov/content/travel/en/us-visas/immigrate/the-immigrant-visa-process/step-10-prepare-for-the-interview.html) and lots of us have shared our interview experiences on the forum if you want to have a hunt. Mine was 2 questions, and super easy. Just take a book or something, I was there for hours, way after my allotted time slot as they were running late.
Good luck.