If you do want to create an account - you can sign-up through Facebook log-in or email.
What I really like about this site is how easy it is to create and join a room - not having to sign-up and have your members remember their log-ins is huge. You also are sent an email afterwards as well with a summary of Instant Meeting online session (includes participants, length of session, as well as any files shared.
summary of session
Embedded below is a GIF followed by a 2 minute and 32 second YouTube tutorial.
I have also included Richard Byrne's video tutorial as well.