This is a BIG question. Pega Platform has many tools designed into it to support this, such as Rule Versioning, Deployment tools (export and import) so that you can simply increment your rule versions, package and deploy them. Without re-typing the course contents here, it's hard to know where to start answering, can you provide more details on which aspects you're interested in specifically?
I didn't receive any. I have designed something(its not OOTB) that might help in achieving this. There is nothing OOTB till 7.1.9. It is said that this feature is being added to 7.2 and I am yet to get an hands-on to it.