Do I need shadow variable? Or Predecessors task and Variable Listeners? I read the document and the projects but it was hard. I could not even write the simpliest implementation as the title mentioned.

ALso if I have Task class (id, deadline) and @PlanningEntity TaskSchedule class (where there is Task task, Date startTime, Date endTime), and @PlanningSolution will have only 2 fields: List tasks, List taskSchedules
when send post request (JSON), can I send an emty list of taskSchedules ?
{“tasks”: [{“id”:1, “deadline:”2024-08-08T01:30:00”},{“id”:2, “deadline:”2024-08-08T05:00:00”}], “taskSchedules “:[]}

When trying testing with other projects, I do not know if I do something wrong, but I have to put values in taskSchedules, even if it only contains @PlanningVariable or else the result will be empty.