View Menu - registered users - sql server 17

Can you tell me where I can find 'Registered Servers', per this information on

'https://docs.microsoft.com/en-us/sql/relational-databases/lesson-1-connecting-to-the-database-engine?view=sql-server-2017'

   If Registered Servers is not displayed, on the View menu, click Registered Servers.

It also refers to File/connect Object Explorer which I am not seeing in my SSMS:

In Management Studio, on the File menu, clickConnect Object Explorer

Any thoughts?

Thanks,

Liz