Forum rules
There are no such things as "stupid" questions. However if you think your question is a bit stupid, then this is the right place for you to post it. Please stick to easy to-the-point questions that you feel people can answer fast. For long and complicated questions prefer the other forums within the support section. Before you post please read this
To extract fonts to /usr/share/fonts you need to do it as root: in a terminal, type "sudo nemo" and copy the font to /usr/share/fonts. Remember that as you've become root now, your home is /home/Your-User-Name. Or you can just copy it to Home/.fonts without doing anything at all (it's hidden, press Ctrl-H to show hidden folders then create it)