I will do my best to answer this question, but I must do so with the disclaimer that I have not written a screenplay. I have looked into it, once, but that was quite a while ago. For the same reason, I don't think I can turn this particular question into an essay, just because I'm not knowledgeable enough on the subject. So, take everything I'm about to say with a grain of salt! The big difference from what I understand is how you go about writing the scenes, and the dialogue. In a book, you would just write things in a big paragraph, but in a screenplay it's kind of designed to separate dialogue from description, and rather than any "he/she/they said", you instead kind of just have whoever's talking at the front of each line. [b]Person A:[/b] So, you would write dialogue something like this. "Not like this." Person A said. A lot of the time you would open a scene with describing how the camera moves throughout it. Like: [quote][i]The camera opens on a decrepit temple at the top of a mountain, made of up a mishmash of stone architecture and gargantuan bones. Our scene transitions to the inside of the temple, where Ludo is sitting upon a stone throne.[/i] [b]Ludo:[/b] I want to learn magic! [i]The camera zooms in on Ludo's face, so that we can only really see his eyes.[/i] [b]Ludo:[/b] *in a gruff voice* Now.[/quote] That's my understanding of it anyway. Someone more knowledgeable in screenplays specifically could probably give more specific advice. It's honestly always seemed a bit easier than writing a novel. Your descriptions can be a lot more "matter of fact" rather than trying to make pretty prose, because the endgoal is for someone else to make it look good with the set, rather than making it look pretty yourself, and descriptions are definitely the hardest part for me. [i]However[/i] I also get the feeling that you're not only asking on how to write a screenplay, but how to get started on writing at all. Like, you got the idea, how do you actually put it to paper. I can give a crack at answering that question, too, if you like.

I'm going to be real with you, I'm super baked right now so I can't be arsed to read that in full, but from what I did read, it's super helpful. this is something that's probably going to require a lot of free time and willpower to sit down and do... I read that a typical screenplay is 90 to 120 pages due to the fact that each page is essentially one minute of screen time and there's absolutely no way that I can write that right now especially considering that the only thing I have laid out are the plot, some tid bits for the first and second act, and the ending.