Cut into the PEX tubing with a pair of PVC pipe cutters to create a joint.
Slip one crimp ring over the ends of the tubing. The ring has to be in place before the fitting is inserted into the tubing.
Push a PEX fitting into the tubing. The fitting should be inserted into the tubing as far as is allowed by the fitting.
The farther the tubing is pushed over the fitting, the better the joint will be.
Slide the crimp ring so the edge of the crimp ring sits 1/8 inch from the end of the tubing. Pull the PEX crimper handles apart to open the jaws of the crimper.
Place the open jaws over one crimp ring at a time. Press the crimper handles together to force the jaws together over the crimp ring.