ᐅ When to apply joint compound or leveling compound after a concrete screed ceiling

Hello everyone,
about 1.5 weeks ago, the screed was installed in our new build. The plaster has been done for a while. Heating can only start in 2 weeks because the pipes for the main house connections have not been laid yet. My question is: from when can we start filling the concrete ceiling (with the appropriate preparation, such as priming with deep primer, etc.)? I have read that you need to be careful about possible moisture to ensure the filler dries properly.
Thank you very much in advance for your help 🙂

You can start with this after the heating program.