Help 2D Animation in 3D Surrounding

[Klaas]

Hi,

so for some reason the issue from my last post disappeared, but now I'm trying to get the Particle system to work. 

I scaled everything up, but the moving particles from the particle system stay in the small scale from before. 
   

I start to feel stupid for all the things I'm asking, but I really tried to get it done. I've got no idea why this doesn't work.

Thanks and best wishes,
Klaas