Mid Chest Variation
To target the middle portion of your chest, anchor the band at about chest height. Then perform the fly movement straight out in front of you, so the bands stay parallel to the floor. This is most similar to a standard flat dumbbell fly.
Upper Chest Variation
For your upper chest, anchor the bands close to the floor. Then perform the fly movement at a slight upward angle. Again, your arms should follow the same angle as the bands. This is most similar to an incline dumbbell fly.
Lower Chest Variation
And for your lower chest, anchor the bands at about head level. Then perform the fly movement at a slight downward angle. Make sure your arms move in the same plane as the bands. This is most similar to a decline dumbbell fly.
Option 2: Single Anchored Resistance Band Chest Fly
With the dual anchored bands, you lose some resistance on the chest muscles at the top of the range of motion. This is because your straight arms take up some of the tension the same way they do on dumbbell flies.
With a single anchored resistance band, you can turn your body about 90 degrees towards the band. This way the tension is greatest when your chest is in the contracted position. And it works more inner chest similar to a cable or pec deck.