Think of a character that has an issue. By that, I mean someone who has a problem. Create reasons why that character would face difficulties in life. Decide on the gender of that character and other information about him or her. That character will be your protagonist.
Then, create other characters who will directly affect your protagonists life. They may be the reason why your protagonist is having a difficult life or they may be the reason why your protagonist wants to do or prove something. It is still important to give detailed descriptions for the secondary characters. Make sure you make them as interesting as the protagonist but not too interesting to overshadow the main character.
Then from there, just expand your story. See, thats how easy to write novel. Why dont you try writing about your characters now?