You need to run a power wire from the battery to the amp, 8 gauge would be suffcient for 100 watt amp, make sure it is fused close to the battery though. You also need to ground the amp, find a solid part of the car withing a foot or so of the amp and sand it down to shiny metal and make that your ground. You need to run RCAs from the HU (front and rear) to the amp and also a remote wire from the HU to the amp (typically blue wire on HU). Lastly you need to hook your speakers up to the amp and set the gains. Go to JL Audio and watch the gain setting tutorial.