Frequently Asked Questions How to set up your Philips Avent breast pump? Your Philips Avent breast pump is designed to easily disassemble and clean. Follow these simple steps to set up your breast pump for your first extraction. Step-by-Step instructions: Begin by sterilizing any of the parts which come into contact with breast milk. Take the breast pump body and fit the white duck valve to this by inserting it into the breast pump from below so that the white duck valve is pointing down. Fit the diaphragm with the stem and fit this to the top of the pump body, pressing down firmly to ensure a good fit. Fit the let-down massage cushion and fit this inside the funnel, again ensuring that there is a good fit. Press your thumb between the petals to ensure no air is trapped. Attach the white plastic handle to the steam and pull to ensure it is fitted properly. Place the cap over the top.