I would like to make appointment at Woodcliff NJ location
I have rather old mac air book and need help updating the new version of MacOs
To install an older version of macOS, read How to download and install macOS - Apple Support. If you run into trouble please write back.
It would help if you identified your particular model MacBook Air: Identify your MacBook Air model - Apple Support.
It shouldn't be necessary to go to an Apple Store, but if you need to do that everything starts with Official Apple Support.