Job offer came in! - any advice?

They called on Wednesday with an offer and I said yes right away. I would rather hear the honest version than the polite one. It is not my dream role, but the pay is fair and the people are kind. How do you handle the first week?

Thanks for writing this out. I went through something close to it 4 months ago, and it got easier once I kept a simple log of every call and form.