First: “Stay in your lane.” You’ve been hired because you bring a certain expertise to the team and the company. Try to resist putting additional or undue pressure on yourself trying to learn it all from day one. It's human nature to feel insecure about everything you "don't know". By staying focused on your core competencies you will be able to contribute much sooner, add greater value long term, and enjoy and have more peace especially in the early days.
I've been following the work of Angela Ahrendts at Burberry for a while. Working with Christopher Bailey they were doing really awe-inspiring work with technolovy, social and physical design at their retail stores. When it was announced that she had left the CEO position to join Apple I was surprised. I've been looking forward to seeing how her sensibilites and perspective will change Apple. Since WWDC this year we've begun to see Apple go through a transition into the next phase of the company. And now to see Ahrendts blog publicly discussing the company and her role in it is such an unexpected move from the secretive company. I am looking forward to the next Apple consumer event where they introduce new products and Ahrendts comes out to discuss the retail operation. It is an exciting time.