Viewing session details or properties

I can create a session and open a session, but how can you view the session properties: host address, port number, username etc.?

Are you asking how to see the settings of an opened session?
WinSCP does not have such screen.
You can enable session logging and inspect the log.
https://winscp.net/eng/docs/ui_pref_logging

People usually do not use WinSCP to open ad-hoc connections. You typically save your settings to a stored site and reuse it. In such case, you can see the settings of your stored site on the Login dialog.