Rebooting after installation of linux

[GreybeardAU]

Using UTM-SE on iPad Pro. IOS version 17.
I have installed and used several versions of Linux. I would like to be able to shut down the Linux and then start again without having to go through the hour long (or more) set up procedure. Each time I restart the Linux it goes through the full installation routine. How do I set up a Master Boot Record after a successful installation — if that is what I have to do. I have tried unmounting the virtual CD as it is rebooting but UTM cannot find an alternate boot disk.

[GreybeardAU]

Have ejected the virtual CD containing the .iso. Result is “no bootable hard drive”. Where does UTM store the virtual bootable hard drive after doing a successful Linux installation?