Hi! The purpose of fcfs.gnunet.org is to make your local zone available to the public. So, the zone key for the local zone you chose is what you'll want to put into the box.
This also answers your question on what you can add to yourSubdomain.pin.gns.alt - anything you can put into a GNS record. Add it to your local zone, and wait for <1h for your node to publish it. The whole Taler and KUDOS thing is an artifact of how GNUNet and GNU Taler have a strong relationship between each other. KUDOS is play money you can get for free from the Taler demo <http://demo.taler.net/>. Please note that pin.gns.alt and anything under it will only resolve under GNS. **These domains do not work for anything that uses regular DNS, including Let's Encrypt.**
