Getting ready to upgrade my OS and apps (bye, FCPStudio, Old Friend!). What I want to do is create a new Apple ID before using the newfangled App Store/iTunes nonsense that I haven't used at home in years. The old ID is associated with my wife's accounts, and I don't want to mix the new stuff with the old. How do I go about it?
If you do a clean install, I believe the two options you are presented with are sign-in with your Apple ID or Create a new ID. That is one way. Here is an article from Apple that explains 3 ways of creating an Apple ID: Create an Apple ID
The easiest is to go to the Apple ID web site: appleid.apple.com and select Create Your Apple ID from the top right of the page next to Sign In. Then use that to sign into iTunes, iCloud, etc. on your Mac.