What does clone button do?

It will create a completely separate copy of the sales message, including building blocks and edited templates in the playbook. This can be good to use when you need to create a similar but slightly different sales message - like different audience but same product.

If you use this, it works best after you have made as many edits and changes as you can before pressing clone so all of those come over and the cloned copy looks as good as it can because after you press clone you will have two independent messages.