Full force like a steamroller. Benefits to this approach You get to write the actual screenplay without having to form the full story. No need to work out plot points or cultivate the characters' personalities. You just write the script. This approach doesn't take much pondering time.
Spontaneous writing is fun and easy.
You activate your right brain when using this approach. Some of the things you write will pleasantly surprise you. Some dialogue the characters say will also surprise you. Once you finish your script you will have a better idea about what you really want to write about. A story and a theme emerge.