I'll explain the other for you.
The pedal on the left is brakes, the peddle in the middle is the shift change pedal, and the pedal on the right is the gas pedal.

This one pianist once explained it to me that way, and it's really accurate sort of.
Regarding your post, I'm actually playing Chopin's Nocturne in E-Minor right now, and my advice would be is to just go by your ear. Don't over do it though, it's very easy to get carried away, and often times my teacher tells me that I should be more careful.
I don't always follow the instructions for pedal use in compositions, I just go by my ear, if it doens't sound like a bunch of trucks making noise, then it's probably ok.
Every measure has it's own pedal embedded into it's rhythm. For example for 3/4, you would put the pedal on 1 and 2, and release on 3, then again.
It's just a matter of being familiar and comfortable with measures and their pedal uses.
Hope that helps.