Usually on day 1, you meet up with your group; have a meet and greet; orientation on how things work, then you usually have a walking tour and a group dinner. All subject to change of course.
Morning start times vary by day. Your guide will post the next day's itinerary the night prior in the hotel lobby. You'll always know what time breakfast service begins and end. You go on your own between that certain time period. If it's a day of changing locations, you'll know what time you need to be down in the lobby with your luggage, etc.
As for the bus; it will be nice and roomy. Breaks will happen about every 1 1/2-2 hours; whether it's a restroom break or meal or destination, etc. You can plan to take your daypack on the bus with you, but can leave things on the bus for the day. Ex. You have your rain jacket and umbrella, but then decide you don't need it for the next stop; so you just leave it on the bus at your seat (or on the shelf above the seat.) I always put a small crossbody bag in my daypack with my phone and wallet, so I can always take those with me but leave the day pack on the bus if I don't need it at the moment. Just remove everything on the bus at the end of the day.
How walking tours are run...just follow your guide. You will have whisper system earbuds for the duration of the tour, (always bring them with you each day) so you just listen and walk where lead.
Your itinerary should be in your portal if not now, soon. Changes definitely can happen. There's a general itinerary on the website. Have a wonderful trip!