I want to hit the ground running > anything you can suggest to ease that transition.

1 > Clear picture in writing of exactly what it is you're supposed to be doing. Nuts and bolts of JD.

2 > Say yes

 Behind the scenes, My function is to serve the greater good.

3 >  Be flexible > Formal job title / description may have little or no relationship to the real work you'll be doing.

"people join companies and leave bosses"

Relationship with supervisor important >

"Smart with energy and a willingness to get the job done whatever it takes" 

"Positive attitude" 

"Enjoy collaboration" 

"Sense of humour" Unless you're working in A&E if you make a mistake no-one is going to die.