Okay, i've read some articles about this, the use of using modes with certain notes etc

But can anyone explain the proper dynamics of it? Like how i would use it in music etc?

A bit vague, but if anyone can enlighten me i'd be very thankful

Also with modes, if say you're in the key of C, and want to use a phyrgian mode, do you have to play C Phrygian or do you just go E phyrgian?