For hard sided bottles, rinse filter for 15 seconds (first time filter use only). Drop in filter and press down firmly until filter is flush with straw. Align lid and straw in unlocked position, and rotate straw to lock. Fill bottle with water, screw on lid, then sip and enjoy. For sport bottles, unscrew mouthpiece and push filter into housing. Replace mouthpiece. Unscrew cap and fill bottle with cold tap water. Tighten cap firmly. Squeeze one full bottle of water through the filter before use. Refill bottle and enjoy.