The difference between using a word processor and actual scriptwriting software is in the formatting. If you use a word processor you will have to set up the formatting yourself (and will take much longer to do) whereas if you use dedicated software it will do the formatting for you.

Scripts can be very simple when you start out but if you get into scriptwriting in a big way for future projects then doing it the right way helps everyone when it comes to shooting. You will have noticed that looking at movie scripts they are set out in a certain way and certain keywords are used, they are done like this as a tv station or movie studio would not accept them done out any other way.

Personally I think it's good to have an already established standard that you can copy and use for setting out your own scripts, it gets you into that professional frame of mind right from the start. Storyboarding is where you draw images to represent key moments in the script in order to visualise how a particular shot will look, again like scripts they can be stick figures when you start out and if you do turn professional then learning to draw or hiring an illustrator will certainly improve the imagery.

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