CorrelationSets in BPEL are as old as the road to Rome. I wrote about it before: 

• PCS and Correlations: the next big thing cavemen already used...
• Use of correlation sets in SOA Suite

Although it was in the BPEL project from the very beginning, when Oracle acquired it in 2004, you might not have dealt with it before. But maybe not even realized that you can use it in Oracle Integration Cloud, with structured processes.

In the first week of june I got to do a presentation about this subject, in a series of Virtual Meetups.

If you weren't able to attend, but would like to watch it then you're in luck, it got recorded by Phil Wilkins:

In my presentation I start with a simple demo based on a BPEL process. I have put the resulting code on GitHub: https://github.com/makker-nl/blog/tree/master/CorrelationDemo. 

Then I move on to a more complicated situation in OIC. I created an export for that project and placed it on GitHub too: https://github.com/makker-nl/blog/tree/master/CorrelationDemoOIC

This allows you to inspect it and try to recreate it yourself.

My sincere appologies for this late sharing.