So here are my first day of school lessons plans.
Really this is a checklist. I've done both-a detailed lesson plan with time assigned to each activity and just a checklist. If I've learned anything in my 15 years of teaching, I've learned that you can't expect anything to go as expected on the first day. And try as I might to follow a lesson plan, it just never goes as planned. So, I just opt for a checklist on the first day and I feel I've accomplished something if I get through most of the list. It always carries over to the second day though.
So you can get my freebie here. I hope it works!