Do I need to wait for a notice to report back to Ganzhou?

You can't go back until you agree to go back. It is suggested that foreigners (returnees) from Jiangxi Province should be tested for 1 nucleic acid at the first place when they enter Jiangxi, and report to local communities (villages), hotels and units after they arrive at their destinations point-to-point. They should be quarantined at home for 3 days, tested for nucleic acid on the third day, and not have meals, parties or crowded places within 7 days.