Purpose of Exercise: To develop strength and mass in the pectoral muscles (middle and upper regions of the pectorals). Also front deltoids are used. Pushing the weight at an incline tends to put extra stress on the upper chest and deltoids. Generally you won't be able to lift as heavy as regular bench press on this exercise.
Execution:
Lie back on the incline bench and grab the bar with a firm grip (same as bench press). Seated on the incline will also isolate your pectorals so no need in positioning your feet. However, do squeeze your shoulder blades together. This enables you to stay tight in the lift. Lower the weight down to the upper chest and pause. Then press it back up to the starting position.
Insider's Tip: It is important to have a spotter on this