Insert the end of your PEX in excess of the top of the fitting. Slide the top in the PEX tubing that has the crimp ring or cinch clamp on it around the tip in the fitting that you screwed on to the copper tubing. Drive it on so far https://marioqxdjn.bloggactif.com/31860749/how-much-you-need-to-expect-you-ll-pay-for-a-good-copper-mip