We need a photo of the whole plant to determine if there is enough vine to take a cutting from. You would root it in the same potting mix.

The plant is huge..too big for my greenhouse.I want to really prune it back so it will fit and try to root some of the cuttings.I have long fiber sphagnum ,coir and reg potting soil,and 1/4 inch pumice. I tried to root some of the cuttings in the sphagnum,but no luck...although i didn't cut the leaves back,just stuck some cuttings in the wet moss and put it out on my balcony in the summer time. Here is the plant.

No photo but here's what to do. I use a 50/50 mix of Perlite and Peat moss. DO NOT use anything with fertilizer added. You can add a handful of orchid bark but it's not critical. Take a 4 leaf node stem cutting, make a 45 degree cut at the bottom. Cut off the bottom leaf near the stem and stick it into the moistened soil so the cut leaf node is down under the soil. Put in bright indirect light and keep moist. It's that easy.

Could also try rooting it in in water. Just make sure it's RO or Rainwater.

I rooted mine in the same potting mix that I use for the CPs. In fact, I even did a rooted cutting by putting it back into the same pot that the mother plant came from.

The main thing is to keep the soil moist. I also chose a cutting which had at least 2 nodes but one should be OK. Stick that node (or two) under the soil.