1. Connect it, switch it on, and
-- 1a. If you are trying to install a HP printer, open a terminal, and type hp-setup.
or 1b. See if there is a printer installation tool in the menu.
or 1c. Open http://localhost:631
in your browser.
2. Search the web for for "Linux Mint install Brother XYZ" or whatever.
3. Tell us what printer it is, what you tried to do, and what happened.