You don't have to do much. The surface works pretty well out of the box. You can use it while you are charging for the first time and doing an update in the background. Heres a few more things to consider:
1. Inspect thoroughly to make sure you got a good model. No dead pixels, micro sd slot works, etc. and everything working fine. It would be tough to install and set everything up, only to end up having it exchanged. I think generally though the quality control is quite good. I have had zero problems with mine so far
2. Make a windows account if you haven't already. you'll want to use that for the surface
3. See if you like the default scaling. 125% or 150% is the default. I personally like 125%
4. Transfer old files and install old programs from old computers