The first thing you will want to do is choose a strong and healthy plant, that's at least 2 years old. Use a vine that looks fresh, healthy, and mostly green.
Using sharp pruners, remove a 2-3 foot section of vine just above a leaf node. Put the freshly cut stem into a cup of water. Plant section with one leaf node and leaves attached. Cut off the rest of the vine 1 inch above the leaf node and 2-3 inches below the leaf node.
Place a small amount of powdered rooting hormone on a small dish or tray. Dampen the end of the cutting with a little water to help the powder adhere, then dip or rub the powder on the lower 2 inches of the stem of each section that you want to grow.
The best way to root these cuttings is in the soil, specifically in a high-quality potting mix. Use a pot with good drainage holes. Soil should be loose, light, and well-drained. Insert the cuttings up to the leaf joint, but not past the joint, and cover the base of the stem with potting soil.
Using room temperature water, water the soil in the pot until it is thoroughly and uniformly moist but not fully saturated and wet.
New roots should form within 4-5 weeks if the cutting succeeds. As long as the cuttings still look green and healthy, continue waiting and keep them moist until about 6-8 weeks after planting the initial cuttings. Any cutting sections that turn brown should be removed promptly.
Hopefully, after about 6-8 weeks, some of your cuttings will have sprouted roots and are ready to be transplanted. Use pots that are 4-6 inches across with good drainage holes. Again, use good quality potting soil and keep the roots moist but not wet.