Subdomains where?

Sorry I’m new to this and I’m trying to get a free subdomain for my raspberry pi using desec
it says you guys allow free subdomains but where,in the web UI you can your own domains but assume those are paid ones since putting does not work and I checked out the documentation but I can’t understand it

Sorry if its obvious I just can’t find it

You might be running into this (hopefully temporary) issue: dynDNS service down? - #3 by peter

Also using something like as your subdomain may not be a good idea. (I don’t know whether deSEC allows this.) Select a subdomain without any periods in the name. You can create entries in that domain later. So in your example you would create, then create entries for example in that zone.

Note that deSEC e.V. is not a domain registrar. The purpose of the subdomains is DNSSEC secured DDNS. It sounds like that is what you intend to to use the subdomain for. But if not, you need to register a domain name elsewhere.