An easy to follow 4-step method to perform a provisional cast-on demonstrated by our friend @PatternsForKnitters.
Step 1: Create a slip knot with your yarn and place it on the crochet hook.
Step 2: Place the knitting needle over the working yarn.
Step 3: Hook the yarn around the crochet hook and create a loop on the hook by pulling the yarn through the slip knot/stitch.
Step 4: Repeat Steps 2-3 until you have the desired number of stitches.