Important Note ... Please read first.
It is recommended to put the archive file on a permanent drive, either the C: drive or a network drive (H:) that isalways attached to you workstation.
Do not put it on a removable drive (flash or thumb drive…). In addition to putting it on a permanent drive you can put a copy of the archive file on a removable device as a backup in case your computer crashes.
Follow these links to instructions on how to archive in Outlook for Mac. The first one is Auto Archive and the second one is Manual Archive:
Auto Archive for MAC:
The Tools menu option that they talk about is in the very top Apple Outlook menu.
Manual Archive MAC:
Follow these links to instructions on how to archive in Outlook for Windows. The first one shows you all the options and has more graphics: