Look in the OS provided “App Store” first - GUI or not, your choice.

Can’t find what you’re looking for? Look for a TRUSTED alternative App Store source. Then check the App Store again.

Still can’t find it? Look to see if there is a package available that your OS can recognize (different based on what flavor of Linux you’re running)

Still can’t find it? See if you can find the code to build the dang thing yourself.