Step 3 - Cut off the ends to the old waterline about 12 inches back or so. If you have white Pex or gray Poly waterlines, a tubing cutter works well (item #50-4860 ).
Step 4 - Locate the materials needed (pictured from left to right for connecting your faucet to existing gray poly waterlines) - 1/2" pex-poly transition fitting (item # 50-5032T), piece of white pex (item #50-4211P) with two 1/2" crimp rings (item #50-5172P) pex to3/8" male shutoff valve (item S50-MISC), 16 or 20" flexible faucet connector (item #40-32590 or #40-3232 or #40-3233 assuming all are 3/8" x 1/2").
If you already have white PEX waterlines, then all you need is the shut-off valve and the faucet connector. The existing waterline will crimp right to the shut-off valve.