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,

Ubuntu 20.04
Dell Precision T1650