You take the power/hot lead going to the radio that turns on/off with the key...we call this "ignition-switched"......and hook that up to the noise filter. Then, take the power/hot out wire of the noise filter and hook that to your radio. You may have to cut your radio's power wire and use crimp connectors to place the filter between the power source and the radio. Lastly, grond the filter.

No offence meant, but have you ever done any type of radio installs or worked around your car's electrical system? If not, then I strongly suggest having a car radio shop, or someone with the experience, install the filter and/or the rest of your equiptment.