Pre-calculating Particles (how to implement)

As in another question here I want to prerender particles. It’s for a background of stars moving down the screen, but at the start of play they have to flow down first.

The other question has an answer, but I don’t understand how to implement it. The answer given was:

// Simulate 10 seconds
for (i = 0; i < 10; i++) {

But where do I put this? I tried making a script and adding it to the emitter with this inside a Start() fucntion, but just got an error.

Thanks for any help given, hope I asked this in the right place (it seems to be a new question even if it’s intimately related to the other question)

Use particleEmitter instead of ParticleEmitter.
better yet, replace the entire thing with particleEmitter.Simulate(10);