The oath ceremony was very nice (virtual). I logged in 15 minutes ahead of time. After a few minutes, they sent me to a Zoom breakout room which was private with a very kind lady. She asked me to show her ID, asked about prohibitions, and asked me to cut up my PR card in front of the camera. I was then sent back to the large Zoom room, and we all waited for a while until everyone (around 140 people) were checked in. They request a plain background (so it's not distracting), but you are allowed to have red and white or a Canadian flag behind you which is what I chose to do. The dress is business attire as it is a serious ceremony.
After everyone was checked in, we were welcomed and they played a video about the Indigenous people of Canada. I believe after that, we all took our oath together with a judge. (They also said it in French, too, but I didn't because I do not know the language.) We then heard from the Prime Minister, which was nice. He welcomed everyone in English and French. The last thing we did was to sing O Canada and then we were allowed to take a selfie with the judge. I felt like it was a well put together ceremony.
I signed my Oath Affirmation form, scanned it, and emailed it to IRCC immediately after the ceremony. That put me in a queue. The next morning I woke up and had an email to log into a portal. I created that account and my e-certificate was there. My advice is to not wait, after the ceremony, to send in your signed Oath Affirmation.
I have now registered to vote federally, provincially, and with my municipality. I am applying for a passport today.
I hope this helps someone who might be anxious about the ceremony.