the key to start hair dynamics?

I’ve been searching now from one hour how to start the hair dynamics simulations in all the videos the people think it’s obvious, but no, it’s not! (it’s even not in the wiki)

Tick the Hair Dynamics tickbox and animate your particle source. Then Bake it in the Particle Cache panel (set start and end frame for cache) to make the playback smoother

Settings Demo:

Thanks Richard I’ll try!

it’s calculating. Is there not a keyboard shortcut for bake button? in the video I heard one say press “Alt e” but it did not work for me…
and it seemed fast…