Owners and co-owners (i.e. in this case delegates) are listed and managed in SIMS. If you are an owner, or a person having a delegated access to the shared account, you see it listed as an identity you own and can modify in Special Identity Management System (SIMS). Calendars can also be shared using the Google Settings interface like any Calendar folder.
When you are granted access to a a shared accounts, you will receive 2 emails in your inbox. These emails inform you of your new access to a shared calendar that will have the same permissions as the Shared Account.
NOTE: Access to the account will take up to an hour to become active. Once active, the account will show up in your list of accounts under your Google Avatar at the top right of your screen.
Clicking on the account you wish to access will open it in a new tab and it will look like a regular email account.