mount – Moving Ubuntu from old HDD to SDD revisited

I am trying to do what was asked – and apparently solved – in a question from about 10 years ago:

How to move ubuntu to an ssd

I want to move an existing, working Ubuntu 20.04 install across to a new SSD and not use the old HDD following the move.

I created a partition on the new SSD using gparted, and booted from a Live DVD as suggested in the top answer in the thread above.

However, when I attempt to mount the new drives (which show up as sda and sdb when I type lsblk at the terminal prompt), the following occurs:

sudo mount /dev/sda

mount: /dev/sda: can't find in /etc/fstab

The same result occurred with

sudo mount /media/sda
mount: /media/sda: can't find in /etc/fstab

and if I try to mount a partition rather than the whole drive:

sudo mount /media/sda1
mount: /dev/sda1: can't find in /etc/fstab.

So, I know it’s a numpty question, but what am I doing wrong? In a way I’m not surprised by these error messages, because the Live DVD Ubuntu presumably doesn’t know anything about the drives on the machine or their partitions in /etc/fstab, since I haven’t told it. But where do I go from here?

I also tried the Nautilus based method described here how to access hard drive files from live cd

Do I need to edit fstab? Strange that none of the 10-years-ago guys mentioned that, if it is the case.

MY other question is that the following page talks about mounting partitions, but the

Many thanks,

Eric
Ubuntu 20.04
Dell Precision T1650