How can I set up Pi Zero2 as AP (and switch between AP and WiFi modes)?

I've been playing around with various configs of raspberry pi as portable LMS devices. It's pretty easy to set a Pi3B+ as an AP after hooking up an ethernet connection.

I have a miniscule server based on a PiZero2 and an SSD drive. Of course the PiZero2 doesn't have an ethernet port. Is there a way to set up the PiZero2 so I can
(a) set up AP mode without an ethernet connection (as far as I can see, to set up AP mode on the Pi3B+ I had to turn off WiFi mode first)
(b) do this in a way that I can switch between AP and regular wifi modes? I'm happy using the command line in a terminal.

The use case would be to use the PiZero2 server in AP mode while travelling, then use it in regular WiFi mode at my destination.

Robert