The conflict is the center of any story. You have a conflict, and subsequently a story but NEVER, ever, the other way around.
When you’re thinking of writing a story, the first thing to think about is the conflict and your plot is to be built around it. If there is none if it seems not to be ideal for whatever you were imagining, then think again. You might not have a story there.
Usually, you have this sort of structure: you have a main character that has a goal, but there is something keeping him from reaching it, a problem to solve, then your character will take action to solve the aforementioned problem, usually other issues and difficulties will be showcased along the way (most provoked by his actions to solve the first one, the big one), then he solves the main problem and the story ends. Simple.
The “problem” might be something as simple as an argument, unrequited love or someone just trying to sabotage your character. It doesn’t need to be (but could very well be) a world-changing problem.
So, how to do it?
It’s actually quite simple and you don’t need to have a tremendous epiphany to start. Usually, when you’re thinking about a story, you have a character in mind. Now, think about a goal for that character. Something that makes them move, tick, or something they otherwise want very much.
Now, the problem. What will actively try or passively keeping him from reaching that goal? Or who? How? What is going to happen?
Now that you have the main part, you just need to think, about what your character is going to do to solve the problem or get rid of their obstacle. These actions will most likely raise new problems and new actions need to be taken to solve them.
And, with this, the hardest part of your job is done! Next, you develop your scenes, starting from this last point onwards to the main goal.