It seems possible (as I learned from a comment to this question made by user55822) to use Artha in order to search a term on the Internet by using "keybinding".

What the aforementioned user says is that

"you could search mouse selection anywhere by using an app like Artha, or by keybinding sh -c 'firefox "http://translate.google.com/#en/fr/$(xclip -o)"' (example given translate english into french)"

A lot of things are obscure for me here. I could use Artha or keybinding (as alternative), or both? How to do that in each case?

and

"The command I gave you will open google translate in Firefox with your mouse selection (text highlighted) as a query. Use sh -c 'firefox "https://www.google.com/search?q=$(xclip -o)"' if you want regular Google over Google translate. And obviously, that would work everywhere"

I do not know what to do with that formula. What should I do exactly? How to use it? In what application?