Starting A Novel

           With all the sources and resources on writing, one thing needs to be stressed: you need a story in order to tell a story.
           Take the idea for your book, first. Whether you scribe it in a notebook or on a computer, make sure that you write it down. You can worry about filling it out later: this is the framework on the house that will be your novel. You can even divide main plot and subplot later.

Starting Your First Novel by Dawn Seewer.

Writing Tutorials by Lauren Halkon

Primary, Secondary, and Supplemental Characters

     So far as I understand it, the primary characters are your heroes, your viewpoint characters, those who undergo the major changes in the story.
     Secondary characters are involved in the minor story arcs that impact the plot, though they are not part of the main story and can be omitted from the synopsis. Secondary characters undergo no real changes to characterization. Quite frequently, secondary characters are the cannon fodder of the literary world.
     Then you have the supplemental characters, who are not part of any arc but are necessary to the story in some way, for background. The barmaid, the Innkeeper, the stable-hand. They do not impact the plot in any way, but are necessary to the atmosphere of the story details.