Hey you getting invaded by your neighbour, the one that promised to never attack you. And NATO persuaded you to give up your nukes for and in return protect you. Whose military are committing atrocities to your civilian populations. You shouldn’t use some of your weapons against them. Because you promised.
Yeah this is pretty weird to me. Maybe focus on what Russians are doing there. The Ukrainians really don’t want to be mining their own country.

They really showed why they weren’t invited in the first place.

Computers communicate to each other over a network. To enable this they open ports where they listen to communication.
A firewall is something you put somewhere in the network to block access to those ports for computers that should not have access.
The firewall can be on a computer or between a network and the internet.