Plotting
How you plot your book will depend on the genre. Some believe in the monomyth but I feel like too many stories are shoehorned into it rather than it being the only way to write a story. I've written romance which is different from mystery which is different again from epic fantasy. Ironically, only one of these genres strictly stick to the Hero's journey.
If you don't like the hero's journey then there is the three act structure which leads to the beats.
I tend towards the beats model. Now I'll talk about Pantsing and Planning. Or if you listen to Brandon Sanderson then you might call them discovery writers.
Pansters
Ironically, for a pantser to do well you need to be very familiar with structure. Because you will be filling in the structure on the fly. The more familiar you are with it the less likely you will get to a point in your story where you get stuck. I'm more of a fan of the term Discovery writer as it allows for more ways than one to be a pantser. Like I always have to write a scene with a character to get a feel for them. Once I know what kind of character they are I can tell what they are going to do in any circumstance. Once I know that I can make an outline. I have to be careful not to go into details as I lose my energy for a story if I know too much. Another approach is the writing into the dark which is very similar to my own style.
Planner
One of the things I like about Romance and also Mystery is you know how it ends and then work back from there. You could do this with other stories. I'm a fan of the Candy Bar Scenes. I then fill out the scenes when I know the key scenes. I personally use the post-it method and a whiteboard with magnets because those darn things never stick for very long. I then put them into a word doc with some random symbol at the start and I can use the find button to make sure I've written all the scenes. If you have Scrivener, it has that built-in along with a place to put your world bible.
I recommend writing a world bible regardless of whether you are a pantser or a planner. Especially if you are writing a series. I have mine on my website and it grows as I write. It is easy to slap up the images that inspire me or graphics I've created for the series.
Writing To Market
Before you start writing I highly recommend thinking about writing to market. Chris Fox has websites and books. But don't write in a genre you aren't familiar with.
Your homework is to find out what style of writer you are.
I also suggest that you start what I call a bad book. Take one of the ideas you have from your previous lesson and then Plot out a story. If you are a pantser or planner you'll be able to find out. But don't pick your best idea. Just one of the good ones. Your bad book is your education. Learn how to finish a book. How many times have you heard that a famous author only got their umpteenth book accepted by a publisher?