I clean installed Ubuntu 20.04.2.0 LTS-Desktop-AMD64 from a DVD written with an ISO image file.
The installation went through its steps, including erasing all partitions and formatting the 1 TB Solid-State drive (SSD) as a single partition.
I then removed the DVD from its drive and rebooted the box. Rather than booting Ubuntu, a single line error message splashed for a fraction of a second (couldn't read it) and GNU GRUB 2.04 was displayed, waiting for a command.
Entering "boot" as a command resulted in an error message saying I have to load a kernel first. Unfortunately the GRUB documentation is of no use to solve the problem.
Why didn't the box booted Ubuntu? How to use GRUB to load a kernel? what files should I specify?