I am strong. I am a
Quick whirlpool engulfing, radially third. You'll use it on puzzle
as sought dead French guy.
But not yet. Wait until you are told to. The puzzle comes here.
I'll even tell you what to do with it.
The first things go first. Go right where you ought
To get mentals collecting toll on road.
Then use my name as it is said above,
try not get engulfed in my vicious love.
This gets you from dark places underground
to shiniest parts of the Moon to be found.
The single "r" is present but in vain,
two first, two second and two first again.
The last thing you have to append here rests.
This is what you have a dozen times first.
There is something strange. Why "a"? Any clue?
This should be one letter that stands for you.
If you followed my directions, you should already know what makes me so strong.
What makes me so strong?
A little hint:
Most of the time you should work on some english word(s), so if you end up with complete gibberish, something went wrong.
Note that the answer to the classic "What am I?" question is essential to proceed, but it is not the final answer to the puzzle.
Progress (according to answers)
The first line of puzzle text and first hint refer to a keyboard layout: QWERTY with ASDFG below. (Xenocacia)
Using a QWERTY keyboard (As found by @Xenocacia), And shifting the the cipher text by one letter to the right and converting "P" to "A", the
"Pnwbra xpogpe" decodes to "Aments caphar". (Sid)
"This is what you have a dozen times first" is referring to the letter 'T', which is the first of all 12 lines of this part of the puzzle (Xenocacia)
"This should be one letter that stands for you." - The letter "U" stands for you (stack reader)
Let's call the first blockquote a "#1", the second one a "#2" and the third one a "#3".
The first six lines of #3 is written in form of "what to do with #2 using #1", "what comes out (let's call it #4)", "what to do with #4 using #1", "what comes out (let's call it #5)".
The other half is some manipulations on the #5 to get the final answer.
Every "ME" in this puzzle (i.e. "My name" in 3rd line) refers to some real world existing object described by the 1st sentence of the 1st blockquote. It is an engulfing whirlpool which is third in the world radially (some google/wikipedia search most probably required). The name is to be used (3rd line) the same way some French guy (who is dead now and knew some ciphers) used to on the current message (which is aments caphar) to get another one.