Process Integration of SAP SFSF Employee Central with SAP S/4HANA Cloud is based on scope item JB1 which requires
certain implementation and operational effort on customer/partner side. Below is a collection of most relevant references to assist you further with these aspects.

Setting up and testing the integration:
SAP publishes scope item JB1 with a newest release each quarter synchronously with the release date of S/4HANA Cloud.
You'll find the newest set-up instructions and test script under https://rapid.sap.com/bp/scopeitems/JB1 

New features you might consider:
Go to the What's New Viewer - SAP S/4HANA Cloud and e.g. search for keyword JB1

When you face problems during implementation / productive usage:
SAP is publishing Tips and Tricks on various issues in this FAQ article with many further references:
2655576 - FAQ: SAP S/4HANA Cloud integration with SFSF EC - SAP ONE Support Launchpad

Blogs: SAP has published background information on this scope item under:
https://blogs.sap.com/2018/05/31/hr-connectivity-in-sap-s4hana-cloud/
https://blogs.sap.com/2018/05/02/sap-s4hana-cloud-integration-sap-successfactors-employee-central/

Complementary information:
The integration scenario is based on an appropriate set-up of your Employee Central tenant. Helpful documentation for this purpose is available under:

General information on Human Resources topics in S/4HANA Cloud: Human Resources - SAP Help Portal