Coaxial cable is used to transfer data from cable companies to coaxial ports in your home. The coaxial signal can be converted to a Category 5 cable signal for connection to modems and other networking equipment. In order to convert the signal, you need only the proper equipment.
Connect one end of your CAT5 cable to the CAT5 (squarish) port on the converter.
Connect the other end of the CAT5 cable to the CAT5 input port on your device.
Connect the coaxial end of your converter to your coaxial device.
Turn your modem on. The modem will indicate that it is receiving a signal.