Can't install for the Relational Databases certificate

Can't install from the instructions given in the link

I followed these instructions to the letter, as I’m not savvy in CLI commands, there were no errors until I got to install the Docker Engine step and inputed these commands:

sudo apt-get update
 $ sudo apt-get install docker-ce docker-ce-cli

Producing these errors:

I googled about my issue but did not find anything that exactly the same. Closest was a recommendation to install docker by using

sudo apt-get install

I’m currently downloading that version as I write this, just hoping I did not shot myself in the foot by doing that.

I’m working on Linux Mint 20.2 uma