Hi Pim,
To effectively work with particles, there is a little learning curve, but (IMHO) worth it.
Please have a look here
https://cineversity.maxon.net/en/series/particles-overview?tutorial=00-particles-overview-introduction
And here
https://cineversity.maxon.net/en/series/particles-objects-settings?tutorial=01-particles-objects-settings-basic-emitter-emission-tab
To go deeper, the Demystify Post Production series (currently running) shares deeper insights.
https://www.youtube.com/watch?v=exHn9hAJXfo
If you are short in time,
https://www.youtube.com/live/exHn9hAJXfo?si=pZ4H9KNNvD1j_9QR&t=4706
Here is an example file for you.
https://stcineversityprod02.blob.core.windows.net/$web/Cineversity_Forum_Support/2024_PROJECTS_DRS/20240518_CV4_2024_drs_24_PAgr_01.c4d.zip
In short, the Collider from Simulation and the Particle system are needed to work with Gravity.
Enjoy