What is Rollover in Futures

What are roll dates in futures trading? Anthony Crudele discusses the significance of futures rollover in this short clip!

[Qliphirot]

Is there no automated system in the platform to roll the open contract at the same time and price?

[BloodCovenant]

When you sell to close one month and buy to open the next month (contract), is cash settled during the transaction, or is it as if you are in the same trade maintaining a contract at the original entry price with all the gains or losses associated with it? I have watched several rollover videos and nobody addresses this question.