Writing about how to build a plot can be very hard because there are so many endless possibilities for stories, and a lot of different ways to come up with them.

There are two ways you can write a novel. One is called planning, and the other is called pantsing. Both have their advantages and disadvantages, and the only way you can figure out which one you are is by writing.

Planning

I'm a planner. The second I come up with an idea for my novel, I'm thinking about how it will end, and possible scenes for the middle. There's a lot of different levels for planning. Some just know the direction their novel is going to go, others write out chapter-by-chapter summaries before they even begin. My level of planning varies with how much focus I want to put into my story. For one of my novels, I know exactly how many chapters there are and every event that happens in each. For another, I know the general direction of where it's going and how it's going to end, but the specific details get fuzzier the further I go, and I don't have them divided into chapters.

Pros of Planning:

Easier to get yourself excited about your story, because you can see the outcome more clearly.

Cons of Planning:

It's harder to change part of your plot if needed or wanted (Although I don't write down any of my planning, which makes it a bit easier because once you write it down, it becomes more permanent)

Over-thinking can be a bad thing. It can wear off all of the creativity and make the plot seem boring when you're actually writing because it feels like you've already written it in your head multiple times

Pantsing

Pantsing comes from the phrase "by the seat of your pants." If you're a pantser, you start of with a beginning with no definite plan of what's going to happen. I tried to pants once, but the results didn't come out very well. Instead of going forward in the plot, I kept using flashbacks and spurting out backstories because I had no idea where to go.

Pros of Pantsing:

It allows more room for your character's actions to drive the plot and shine through

The plot can be more unpredictable and therefore more exciting because not even you as the author can predict what's going to happen.

Cons of Pantsing:

You can accidently write yourself into boring or impossible-to-get-out-of situations, making you backtrack or start over.

It's harder to create foreshadowing and mystery.

It's usually pretty easy to tell which one you are, and one should make writing more easy for you.

What a plot needs:

I learned in first grade the basic idea of a plot, and they way they taught it still sticks. They called it C.L.A.P.S.

C: Character

To have a plot, you need at least one character. It doesn't have to be human, or even alive. You could write a story from the view of a pencil, or death, or joy. (Example: Bob is a squirrel)

L: Location

There needs to be a place. Pretty straight forward. (Example: Bob lives in a tree)

A: Action

The character(s) need to do something. They also need to want something or have a goal. (Example: Bob wants ice cream, so he leaves his tree)

P: Problem

Something or someone should be preventing the character's wants from being met. (Example: To get ice cream, Bob has to cross the interstate. He could easily get run over)

S: Solution

The character's story has to end. Sometimes, the character's wants aren't met, but this is still considered a solution. (Example: Bob finds his friend, Rick the Moose, and rides on Rick across the interstate to the ice cream place. Rick is big enough that cars see him and stop, OR Bob decides it's too risky and eats some nuts from his tree instead)

This should be the overall main plot, from there you can add in subplots, which are also actions, problems, and solutions but don't connect to the main plot so directly.