With the saline felt pad facing inwards, place it over the Sensor hole into which you wish to fit it. Flipping the Cap inside out, stretch the hole over the Sensor, let the material pop into place into the plastic groove. The majority of the Sensor should be on the outer side, while the felt should protrude towards the inside, where it will be resting against the scalp when the cap is in place. Repeat this step for all Sensors.