Hi Stefan,
Short page content description http://docs.gantry.org/gantry5/particles/page-content
“I added the openstreetmap particel, but it stays grey whatever i tried to configure.”
Did you check the openstreet documentation before ? See https://joomlead.com/g5/docs/open-street-map-particle/
NOTE: Make sure the openstreet css/js files are loaded correctly.
Thank you