I try to set scheduled backup job for our buckets S3. How to manage such job inside Amazon S3 bucket?
I am not sure I get entirely what you are asking. S3 is very very VERY reliable and offers something like 10 9’s of durability. So it protects your data by replication and is protected against natural disasters etc because it is never all in one data availability zone (aka all in one data center).
It of course doesn’t protect you from yourself and deleting objects. That is where object versioning comes in. Perhaps read the following article and follow the steps to turn it on and you should more than safe.
I hope this is what you were asking. 
I will need to check. It is also a feeling effect due to security as the second chance .