You have three choices.
Follow the instructions above. The disadvantage of this is that the host computer that the printer is physically connected to must be switched on in order for the other computers to connect to it and print.
Fit your printer with a ethernet network card and have full network access. This is a much more complicated option and not one recommended for newbies.
Buy a print server (TP-Link PS310U at around £25 for example) which connects to the network and to which you connect your USB printer. The printer is then available to all computers on the network without the need for a master computer to be switched on as the print server is connected to a spare ethernet port on your router.
Depends on what kind of access you want. Option 1 is the simplest.