If you're interested in game designing process but have no idea about the GDD format, as well as its content, I can help you with that.
Since I'm an game designer who has worked for 15+ indie game projects, I can show you my GDD format which I'm using right now, with notes describing every part so you will know which step to take.
I hope that you can use my format as a start to begin your dream career, and even invent a GDD format of your own.
Please be aware that I'm not going to design a game for you. You'll get from this gig my favorite GDD format which I'm using right now to communicate with other guy in our team.