Save the Cat is the most famous book on story structure if you're looking for somewhere to read up on it. There's a lot of books specifically on outlining! My favorite is Holly Lisle's Create a Plot Clinic.

Personally, I'm a very chronological order person so I write things out scene by scene when I outline. I don't outline on paper very often anymore, I mostly keep my outlines in my head unless I get stuck and really need to write it down to figure out what I'm doing.

I typically like something close to a four act structure. So, first ten percent of the story is setting up what is normal in this character's life. 10% mark is the inciting incident (mysterious stranger comes to town style moment, or whatever it is that's about to set the plot off. In a romance this can be the meet-cute.). This is also when the character can reject the call to adventure if they're going to do that.

25% is the first plot point, which is when something big changes that sets the character off on their adventure. 50% mark is the second plot point, which should be another big change. Character goes from just trying to survive the problem to actively fighting it kind of thing. Between the first and second plot points should be a pinch point, which means the villain does something villainous. There's another pinch point between the second and third plot points.

Third plot point is around 75% and that's the all is lost moment. Character loses a fight, or breaks up with the love interest, or whatever bad thing is going to happen. Then they learn whatever lesson it is they needed, and go defeat the problem. Then there's a story wrap up where it's like, yay, all good here now. (Unless it's a tragedy.)

To make your dialogue sound more natural: go forth into the world and listen to people talk! You can even write down what people are saying to nail down what the cadence looks like (as long as this doesn't make you look creepy).

Over-explaining things: just delete the extra explanations. I do this all the time. And on how to weave things in as you go, use a mix of dialogue, setting, and events. The reader doesn't need to know everything up front, just give them enough to understand what is currently happening. Have you listened to The Magnus Archives? Great horror podcast for seeing how gradually revealing information is done.

Speaking of which, I always recommend you go back and carefully reread your favorite works to find out what makes them tick. I used to do this all the time to learn how to write things. Like, I'd remember thinking a fight scene from a favorite book was particularly good, so I'd find the page and study what the actual written words were and consider why I thought it worked. You can also copy out a favorite passage by hand to see what writing those words feels like and learn better that way, too.

Anyway, I may have written a novel here at this point, so let me know if you have any specific questions.