Let's work on the above mentioned steps one at a time. Before we begin, ensure that you keep the story structure, the no of players very very simple.
Q.6 You have a theme in mind. What is your main idea of the story that supports that theme. Let's brainstorm.
Q.7 Questions to help build story structure
Let's move to the story structure. Let's answer a few questions that will help us build the structure
Imagine the settings... Where do you want the story to begin? Is it outdoors? Indoors?
Q.8 Who is the main character of your story?
Q.9 what happens in the beginning of the story?
Q.10 Any story comes with challenges / problems or as we call it "Conflict". That's what makes the story interesting. And that is exactly what will make a board game interesting. Let's list down the challenges that can come up .. atleast 5 , we can narrow it down later.
Q.11 Every problem has to have a solution. For all the challenges that you had come up with in the earlier question, formulate the solution
Q.12 Choose the best 3 challenges and corresponding solutions.
Q.13 Make a list of characters that is needed. Preferable to keep the characters ( i.e players for board game) to a minimum of 4. Since it is the first board game you are designing, it is wise to start with just 2 players.
Q.14 Combine the entire story .. let's see how it looks when its put together.