I have described writing a novel as akin to building a house. For me, the overall concept is in my mind. The blank paper is the land where the house will be built. Most of the building materials are on the truck waiting to be unloaded. The only problem for me is I do not have any blue-prints to follow so I have to figure out where everything goes without direction. Many writers outline carefully (blue-print) and some synopsize from beginning to end (build a scale model). I synopsize after the fact (more or less jotting down where I have been after a few chapters so I have reference to the thousands of words already written). I am more or less considered a "pantser" (flying by the seat of my pants) and it is a method frowned upon by most experts.
Another way to look at the process of novel writing is as if you are on a cross-country journey. The first couple of hundred miles are more or less a straight run on the interstate and you just breeze along with nary a bump in the road. Suddenly there is an unexpected detour ahead and you are sent in another direction. You make a wrong turn and discover that you have no idea where you are. Where is that darn highway? You stop and ask directions (thinking) and write them down (different ideas) and the person who gave you directions becomes a new character. You begin to drive and "thumpa-thumpa," you blow a tire. Uh oh--the spare is flat. You have had enough and decide to stop at a motel so you can relax and regroup. Ultimately, you fight through the adversity (write-edit-write-edit-write) and keep on going.
I hope you get my point with all of this. You will always hit the proverbial "bump in the road". Sometimes you will wind up in a ditch. You have to deal head-on with all obstacles. The goal is to finish the journey. The entire process will more than likely prove to be a lot more challenging than you ever thought. But you MUST keep on truckin' - sooner or later you will reach the end of the journey.
Sidebar: If some of the young folks out there would like to get an idea of how it might be to have to fend for themselves and take care of the "business of life" they might enjoy reading The Priest & The Peaches. Not all kids come home to an X-Box 360 or a Wii, and a mom who is there to feed them and tuck them in.