[RWP] How to access effect parameters?

[Crystal Dennis]

Sorry if this is a question that's been answered before but I've
searched through the archives and can't find an answer.

I've been trying to access the parameters of...any plug in really:
not the ones that come with Reaper, but some that I added, and I can't
see anywhere to mess with the parameters (ratio and threshold on
compresser, the bands on EQ etc).  I use JAWS 10 and have been looking
around both with tab and the JAWS cursor, but can't find anywhere to
adjust those things.  Can someone help with what I should be doing?  I
just use F to add the plug then look at that window:  is that not the
right way to be able to adjust parameters?

Thanks,
Crystal