I hope his first move is not renewing the contracts of the entire coaching staff.
Now he needs to fire everyone else...
I think new coaches are obvious, but I'd be very surprised if he completely cleaned house. For one thing, Toboni has been described as very people-focused. It's what has separated him from other candidates that are scouts and/or analytics-based. Its unlikely someone that values people in that way will just come in and make cuts en masse. But also, Toboni has survived multiple regime changes in Boston. Not only has he survived, but he has thrived. Three other PoBOs have not only seen fit to keep him, but rapidly promote him in an attempt to keep him. So I'd be very surprised if he came in and just cut everyone. I expect that he will add and remove people over the course of the next 2-3 years.
Which brings me to another point. Barring a massive about-face in spending by the Lerners, this will likely not be a quick turnaround for this team. We won't see the fruits of Toboni's improvement in scouting, drafting, and player development for 3-5 years. But hopefully, hiring a guy so young means they intend to stick with him for long enough to maybe turn this partially around.