Pretty easy interview for me.
A mask is required to enter the facility. Once you enter, you have to show your letter to the security guard. He will have you put all your metallic things in a tupperware box and have it scanned, like at the airport.
You walk through a metal detector and then get given a numbered window, where they take your fingerprints and your photo, then direct you to wait upstairs.
I waited about 5 min before the IO came out. She had me swear that I would tell the truth, then gave me the test. She asked me a few questions and had me review my form. Then, I went downstairs and had my picture taken at another numbered window (for the certificate) and that was it.
By the time I walked out of the building and got back in the car, my oath ceremony letter was in myUSCIS.