Gae,
I have mine running off a pen drive, what I did was create a bootable image with ISO on a pen drive from the download with rufus.
Then I put a second blank pen drive in the usb slot beside the bootable one and booted…… this then starts the system and once up and running use the the firmwatpre tab in settings which let me install the system onto the second pen drive and remove the first.
Once booting from the second pen drive you are now not running read only.
In theory you might be able to do it all from one pen drive but that then wipes your install pen drive and if you make a mistake you need to use rufus again.
I have mine running off a pen drive, what I did was create a bootable image with ISO on a pen drive from the download with rufus.
Then I put a second blank pen drive in the usb slot beside the bootable one and booted…… this then starts the system and once up and running use the the firmwatpre tab in settings which let me install the system onto the second pen drive and remove the first.
Once booting from the second pen drive you are now not running read only.
In theory you might be able to do it all from one pen drive but that then wipes your install pen drive and if you make a mistake you need to use rufus again.