Installing etcher on ubuntu

I am trying to follow the x86 installation instructions. I have got ubuntu running from usb and trying to install etcher in order to flash home assistant to the ssd.

I tried using appimage, following the instructions here: How to Install Etcher, the USB Writing Tool, on Ubuntu - OMG! Ubuntu!

When i double click to run etcher nothing happens and if i right click and run i get the following error


I have also tried installing using terminal following this video: How to install BalenaEtcher on Ubuntu 20.04 - YouTube
I am getting this error:

I am completely new to this so any help in noob language appreciated

there is no need to use this software when ubuntu is running…

dd if=blabla.img of=/dev/… bs=4M

Note: be CAREFUL where you write it with of=. Must be the stick/sdcard!

Thanks for the reply but I ended up taking the SSD out of the laptop and using a usb adaptor to flash it from pc