Just received a pair of pre-paired nRAYs, the "Wireless Wire" kit.
Followed the directions here: https://help.mikrotik.com/docs/display/UM/nRAY+series
Grabbed laptop, set it's IP to 192.168.88.100, plugged straight into the master, changed its static IP to my LAN subnet using WinBox. Got it onto my LAN no fuss no muss.
Sat down at my main PC and using WinBox could not get the Quick Set upgrade feature to work, it complained about no internet access. So I upgraded manually by downloading routeros-7.13.2-arm64.npk and dragging it into the root of the files window, then rebooting, in accordance with the ROS doc's.
The nRAY came back up indicating 7.13.2 and could now find the internet, but there are no longer any entries in WinBox for the W60G radio and all of the pre-paired 60G radio config. is gone.

What did I do wrong and what are my next steps, please?

What you did wrong: manually upgrade by dropping package on Files.
What you should have done: upgrade through CLI or Winbox, then there would have been 1 package more on your device.

Since 7.13 routeros base package does NOT include legacy wireless drivers anymore (which are needed for 60G radios).
So you need to add wireless package as well.

• Install package
• Reboot
• Reset to default config
• Start config

WORST CASE:

• netinstall using 7.12
• upgrade (through CLI or Winbox) to 7.13.x

Could be someone actually using this device might chime in with better options.

See here for more info (release notes, helps sometimes to read them ):
viewtopic.php?t=202423

2. Drivers for older wireless and 60GHz interfaces, as well as the wireless management system CAPsMAN, are now part of a separate "wireless" package instead of being a part of the bundle package. This package can be uninstalled if not needed.

You do need it. So add it.

What you did wrong: manually upgrade by dropping package on Files.
What you should have done: upgrade through CLI or Winbox, then there would have been 1 package more on your device.

I tried to do it via WinBox but the delivered config. 6.xxx (can't remember the exact version) refused to perform the auto-update. I found the instructions online to do the drag and drop method. That method worked 100% fine.

Since 7.13 routeros base package does NOT include legacy wireless drivers anymore (which are needed for 60G radios).
So you need to add wireless package as well.

• Install package
• Reboot
• Reset to default config
• Start config

I'm new to MicroTik (but an old hand at Unifi). When I looked at the list of the two packages, I had thought it was "either/or", not "both". At least it was a basic error

Easily fixed. I had already rebooted after loading the updated RouterOS. I drag and dropped the wireless package, rebooted, and all is well, configuration was preserved.

Question for the future: when more than one package needs to be loaded can they both be dropped into the files window prior to a reboot, or is it first package-reboot-second package-reboot?

Thanks!

I tried to do it via WinBox but the delivered config. 6.xxx (can't remember the exact version) refused to perform the auto-update. I found the instructions online to do the drag and drop method. That method worked 100% fine.

Except ... with 7.13 comes the requirement you FIRST have to upgrade to 7.12.x and only THEN 7.13 will automatically take care of missing packages, transfer of wifi/wireless config to the right place etc.
It's clearly mentioned in the release notes for 7.13 which few seem to read.

Question for the future: when more than one package needs to be loaded can they both be dropped into the files window prior to a reboot, or is it first package-reboot-second package-reboot?

Depends but most of the times, both at the same time will do.
But upgrade using CLI or Winbox/Webfig is always better in case some "behind-the-scenes-stuff" needs to happen (see response above).