Insert the top in the PEX about the end in the fitting. Slide the top of the PEX tubing that has the crimp ring or cinch clamp on it more than the top in the fitting that you screwed on to the copper tubing. Press it on as far as https://damienpvbhm.ja-blog.com/32144562/a-secret-weapon-for-1-2-inch-copper-street-90