step by step for reactor particles?

I must be dim. I can’t find a “getting started” for reactor particles and nothing I’ve tried has generated any results.

I created a plane and made it emit particles with a life of 50. CTRL-A… success.
I want to add a reactor to that particle system, so I click on “Add New” on the plane’s particle system… hmm… that didn’t work. Ok… I have to make a new object?
Hmm… ok, I switch my first plane back to emitter.
I add a second plane and make its particle system a reactor. I leave all the settings at default, except I set “Target” to be “Plane”. CTRL-A… umm… no reactor particles… ???

All the documentation google is turning up is for old versions of the particle system. :confused:

Many thanks, sorry for the trouble.

Ok… I just found the “emit from” and was able to change it to “Particle”… things are starting to work… would love some documentation though, if anyone has a link!