Google app vs Google Now app - what's the difference?

Kind of confusing. Google Now is listed as a launcher, will installing it mess up the BB launcher?

This title question stems from the fact that I can't seem to do any voice commands. When I press on the 0/mic key the microphone icon in RH lower corner is greyed out with a line through it.

So what allows the assistant to work so I can voice in notes, texts and emails?
(btw, I currently have 'Google' disabled in Settings>Apps)

I want to be able to do like I did on my Classic. Just press a key and say "new note the grandma is almost out of pills"