How to play the French Defense?


The French Defense is tricky and highly defensive for quite a few moves. I'd recommend starting with symmetry and copying moves instead, for as long as it is safe to do so: 1. e4 e5, or 1. d4 d5, or 1. c4 c5, etc., unless you want to jump right to trickier openings, or openings whose players or names appeal to you. At any rate, there are online databases, some free, that will answer at least half of your opening questions.

You should not be studying openings, and focusing on Endgames, Tactics, Strategy, and Opening Concepts.
Clearly you are not ready for opening theory given both the fact that your highest rating is your bullet rating at 1236 and that you utter the statement that the King's Gambit is only good for White? PA-LEEZ! First off, the King's Gambit is a joke and Black starts the game off slightly better, and it's White fighting for a draw. As for the Fried Liver, any chess player that isn't completely clueless wouldn't ever allow the Fried Liver.
After 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 d5 5.exd5, the move to play is 5...Na5! (5...Nxd5, allowing the Fried Liver, is complete garbage for Black).
... Clearly you are not ready for opening theory given both the fact that your highest rating is your bullet rating at 1236 and that you utter the statement that the King's Gambit is only good for White? PA-LEEZ! First off, the King's Gambit is a joke and Black starts the game off slightly better, ...
I thought SexyYaoiPrince was just alluding to the observation that Black is unable to choose to be in a King's Gambit opening.
"... It is well worth experimenting with [the King's Gambit] ..." - GM Gabor Kallai (1997)
"... For beginning players, [Discovering Chess Openings by GM John Emms] will offer an opportunity to start out on the right foot and really get a feel for what is happening on the board. ..." - FM Carsten Hansen (2006)
https://web.archive.org/web/20140627114655/http://www.chesscafe.com/text/hansen91.pdf
"... Once you identify an opening you really like and wish to learn in more depth, then should you pick up a book on a particular opening or variation. Start with ones that explain the opening variations and are not just meant for advanced players. ..." - Dan Heisman (2001)
https://web.archive.org/web/20140626180930/http://www.chesscafe.com/text/heisman06.pdf
Possibly helpful:
First Steps: The French
https://www.newinchess.com/media/wysiwyg/product_pdf/7611.pdf
https://new.uschess.org/news/how-to-really-learn-an-opening-review-first-steps-the-french/