BI 4.1- Increment versions of the Webi report into CMC and being able to roll back

Hi experts, please help me answer below questions

1. when do I increment the version and HOW to do it?

2. how to rollback to previous version?

3. Any document that outlines the entire strategy from start to finish.  What things need to be implemented?  What new procedures will developers do?

Any solutions or documents will be quite appreciated

Thanks, Kris