Sure… no sweat… you’ll need an external storage drive with the same capacity ( or greater) than your MacBook Air…connect it to your MacBook Air, you can use Disk Utility to make it Mac-formatted, then eject the drive ( safe eject) then when it’s done so, you can disconnect it from your MacBookAir. shut it down, connect your external storage drive, then power it up with the drive connected… on your MBA, navigate to Time Machine, click on it, turn it on, and pick your external drive as where you want to do/make a backup… then click on “ Do a backup” and it’ll do it.. it’ll transfer all your data safely, securely , reliably and completely. AFTER it’s done for Sure.. then maybe erase your MacBook Air with Disk Utility…
that’s all, teasalorain0629, at least from me
John B