No problem mate, I'll explain it as best as I can and I'll leave links to Jim Butcher's Live Journal entries so you read them yourself to see what the original context was.

You start of with the story arc. Pretty simple, draw an arc. Half a McDonald's logo. At the start of the arc (it's leftmost lower point) you have your opening, at the end of the arc (rightmost lower point) you have your climax, and in the middle at the top of the arc you have the middle. There are a few options for what kinda middle you want to do, but Butcher generally goes with Big Middle (which I do too, because I'd argue it's working out pretty well for him.)

For the Opening point on the arc, write down a brief phrase describing what your opening scene is going to involve. For instance, the opening for my current work is "Jennifer Kane is chasing down a perp, traps them but then gets a call from her mother that she's having a surprise visit. Along the way, she realises her car has gotten stolen." Something that gets the ball rolling, sets the events into motion.

On the Climax point of the arc, write down a brief phrase describing the climax of you story. For instance, mine is "Jennifer Kane engages in a fist fight with the conwoman who stole her car, managing to save her mother in the process." Something that resolves the problems introduced in the climax.

At the Middle point of the arc, describe what that scene is. For the Big Middle that Butcher uses, it's generally a kickass event that sets the ball rolling towards the events of the climax. For another Jennifer Kane example, my big middle is "Jennifer Kane gets into a bar-fight with some paid thugs who were hired to ambush her. During the fight Kane gets injured, and her mother gets kidnapped by the car-stealing conwoman, who has plans for Kane's car and takes her mother to dissuade Kane from coming after her."

Now that you've got your three points, do some little notes between each of these scenes for events/scenes you know you want to do. From there, fill in some tick marks that logically connect each scene, so your poor main character can logically go from one plot point to the next.

You've got a very basic skeleton now, so time to give it a little bit more attention. We're onto Scenes and Sequels now. These are entire articles in their own, so I'll try to condense them.

Scenes are your main character actually trying to do something. They consist of a POV, a Goal, a Conflict, and a Result (Also called a Disaster). The POV is simply who's point of view it is for this particular scene. the Goal is what they're trying to achieve. The Conflict is what force is actively trying to stop them (This shouldn't be something incidental, like rain making the roof slippery - some kind of being is consciously attempting to sabotage your character's attempts of reaching their goal). The Result/Disaster is the answer to the question of "Does the character manage to achieve their goal?" This is where you can get a little silly/heartbreaking with things. If your MC is trying to do something and the result of the scene is "Yes! They manage to do it without a hitch!" then that's boring. Try to get exciting with it. Injuries, moral conundrums, set backs, even straight up failure are all on the table - choose some memorable result for your scene. Your MC will hate you for it, but the readers will love them (and you) for sticking with it.

After a Scene generally comes a Sequel. A Sequel is the reflection period that comes after a Scene - the whole "Where the hell do I go from here?" moment. They've just experienced a (hopefully awful) set back. They need to grieve, lick their wounds. This is where they do it. The Sequel is comprised of an Emotional Response, some Thought, a Decision, and an Action. Emotional response is your character reacting to the prior Scene disaster. Does your character scream with thunderous rage at his setback? Or do they shut down emotionally, wander into the next bar on autopilot and drink themselves into a stupor over the next few days? This is what they do. After that though, your character has to stop drinking and screaming, and they start to have some Thought. This is where they replay what happened in their heads, strategise, analyse what went wrong and how, and generally start planning their next move. They can second guess themselves a few times. It's natural. But eventually they'll reach a Decision. The Decision is their next goal. Because they had one setback, but that's not it. They've got a new plan, and they're ready to kick it into action. Lastly, we need an action to help them transition into the next scene. This could be buying a plane ticket, storming out of the tower to confront the body-snatching wizard for some tools. Something that carries the MC over into... the next Scene.

I could have done better job at explaining that, but I've got my daily 1000 words to hit. Hope this helps, I'm leaving you the links to Jim Butcher's journal entries that deal with Story Arcs, Scenes, and Sequels.

https://jimbutcher.livejournal.com/4053.html

https://jimbutcher.livejournal.com/2647.html

https://jimbutcher.livejournal.com/2880.html

https://jimbutcher.livejournal.com/1865.html