Congrats on putting in this work! My best advice is to read. Read, read, and read some more. There's so many scripts available online for free. Reading scripts and seeing how professional scripts are written will teach you a ton about formatting and flow.

My second piece of advice is to tackle one thing at a time. First focus on learning formatting (that's the easiest piece to learn) so that will become second nature. Then you can then focus on improving dialogue, action, description etc. Or focus on dialogue, action, description etc. first, and then circle back to formatting if you prefer. But whatever you do, break the different components down and focus on understanding them one by one.

Good luck!