Choose a suitable position for installing the stereo system and speakers. Keep in mind that speakers direct the sound in the direction they are facing, which greatly influences the position you choose. Also, in most cases, stereo systems need to be installed at an angle less than 30 degrees to prevent any damage from shock. Choose a location that is safe and out of reach of any water spills caused by water waves if your stereo system is not waterproof.
Drill holes for mounting the stereo system's splash cover and for passing the cables through. Make two holes for screwing in the splash covers and two more for the power cable that will lead and join to the common power bus and the speaker.
Mount the stereo system in the selected area using screws or mounting brackets that are usually bought together with the system. Open the dashboard panel using the screwdriver to uncover the common power bus for the boat's electrical accessories then direct the power cable from the stereo through one of the drilled holes and route it to the power bus in the dashboard panel.
Connect the stereo cable to the common power bus by inserting the male connector on the stereo cable to the female connector slot on the power bus.
Install the speakers into their selected locations. Drill holes to mount the speakers in and firmly fix the screws to hold them in place. Connect speaker wires to both the positive and negative speaker terminals for all the speakers in the system. Route the wires to the stereo system and match each wire to its respective terminal; the wire from the positive speaker terminal connects to the positive terminal on the stereo and the negative wire to the negative terminal.