All your delegated subdomains display in the Channels / Subdomains menu. Filters are available to help you refine the list (delegation date, user or status).
The Status column provides information on the subdomain delegation process:
To access detailed information about a subdomain, open it from the list. You can:
Retrieve the subdomain name (read-only) configured during the delegation process, as well as the generated URLs (resources, mirror pages, tracking URLs),
Add a Google site verification TXT record to your subdomain to ensure that it is verified (see Add a Google TXT record to a subdomain).