Recline and place Sensate on the centre line of your chest bone about 3-4 fingers below the top of the bone (you can feel the notch at the base of your throat where the chest bone starts). Sensate can be used between the breasts and as low as the lower part of the chest bone, depending on your shape. Feel free to experiment with slightly different positions and see what feels best for you.
The series of illustrations and descriptions in the User Guide show the region Sensate can be used on. It is a region rather than an exact spot as the device only needs to be placed flat on the midline of the chest bone for the bone conduction to work. The Sensate is meant to be positioned near to your sternum. You can move your device up or down a few centimetres or so depending on your shape and where it feels good.
You can use Sensate on top of or between clothes, directly on the skin or inside the neoprene pouch.