https://www.epo.org/en/service-support/faq/applying-patent/cnipa-epo-pilot-programme/conditions-participating-cnipa-epo-2

Where do I file my international application if I want to participate in the pilot?

To participate in the pilot, you must file your international application with either the CNIPA or the IB acting as receiving Office.

The EPO is not a competent receiving Office for international applications filed by nationals or residents of P.R. China.

All application documents (request, description, claims, any drawings and abstract) must be filed with the receiving Office (the CNIPA or the IB). If the CNIPA is the receiving Office, the documents should be filed via the CNIPA's CE-PCT system. If the IB is the receiving Office, they can be filed using WIPO's ePCT filing tool.