Set the bench so the incline is at a 30-degree angle to work your chest muscles. To train your shoulders, biceps or triceps, raise the incline up to a 40-degree angle. Muscle & Strength reports in the article "Incline Bench Press Video & Instructions" that an incline greater than 30-degrees activates your shoulder muscles, thus making such a steep incline only appropriate when performing non-chest upper body exercises.
Press against the inclined portion of the bench to ensure it is locked into place before sitting.
Position your buttocks on the bench's seat and grab your dumbbells if you are not using a barbell.
Lean back into the incline until your entire back is supported by the bench. Keep your feet flat on the floor or on the foot rest bars.
Perform the exercise while keeping your lower back pressed into the bench and taking deep breaths.