Practice, practice, practice... That's the KEY!
If you're not a writer and you want to learn how to write a script for any style of video, then it's always recommended doing it yourself again and again (make mistake and rewrite). Scripting needs practicing, keeping in mind about what you are writing should reflect a story. It is very important that you not just watch movies and read scripts, but that you actually learn how to write a script. The script has to be proper and must stay connected with the storyline. The other way around is to go directly to a professional script writing company, however scripting should come from your own mind, and that's how the originality comes forward.
In the last few years, there has been a big shift in how videos are being created. In the past, there was a clear distinction between scripted content and non-scripted content, but in the current time, most video content is being created with a script and a storyboard in mind. Writing a script for a business video is as similar as writing a script for a film. It’s a process that can take a week or even a month (for large projects such as web series), depending on how much you have to communicate in a limited amount of time. A script is a roadmap that helps a director and a crew get from point A to point B.
Let's simplify. A script is a list of scenes that need to be shot. It is the story that the director, cast and crew need to shoot, but it is also the most important part of filming, either for a corporate video or a full featured web series. A script is not an outline, it's the story itself, the scenes that you will shoot. Before you write a script for any video medium, you must have a clear idea of what you want to do, and what is the objective behind a story. We all must have seen when the screenwriter makes changes to the script after shooting. After shooting, the DOP (Director of Photography) may suggest changes that the Screenwriter agrees with or may not agree with. One of the more common mistakes is to fix a script that doesn't work, which wastes a lot of resources and time. In such scenarios, the original version of the script might get changes.
So, plan ahead about the purpose of video, and get started with scripting. Make mistakes and rewrite.