A script concept is a way to describe the idea that will help sell the script. It is the "hook" that captures a reader's interest.
The treatment is a shortened way of describing the script. It does not go into detail and can be used as an outline or to pitch an idea to a producer.
This is the detailed outline of the script. It's basically a fleshed out version of the treatment.
The script format is the way in which the scenes, description and dialogue are written. It is a standard format in the industry that must be followed.
All scripts need interesting main and supporting characters who have needs that must be fulfilled. Proper characterization drives a script forward.
Plot is the story that is told by the script. The plot is divided into three acts---a beginning, middle and end.
Character conflict is what moves the plot from its introduction (the beginning of Act One) to its resolution and climax (the end of Act Three).