Congrats on acceptance! I wasn't even in the country when I got accepted last year and I didn't get back until after the initial document deadline. I just let them know via email and they were pretty understanding and accommodating, so you should be fine, especially since the world is a lot messier this year compared to last.
They did it automatically for me (but I also graduated that year so idk). The class schedule will eventually be delivered to you via another website since beartracks freaks out and can't understand how to show the schedule properly. The end date was supposed to be the 17th of July this year, so I anticipate that it'll be similar for you guys but naturally everything is subject to change depending on the impact of COVID.
Looking forward to meeting you all and hope you're looking forward to an unique orientation and dental school experience lol