Nikolas has given you an excellent and very helpful response.
When you say you're a beginner, I'm wondering if you mean a beginner at composing music, or that you just don't have experience at composing for film?
Music for movies - It's safe to say that in the course of film history every genre of music imagineable has been used in soundtracks. There are always current trends and popular preferences in the kind of music used. For quite awhile now we've been in the Big European Orchestral era, as exemplified by John Williams. But that isn't the only kind of music being used in films nowadays, by any means.
My point is that there really isn't a specific "film style." There are certainly movie music cliches - but those you'd want to avoid. Whatever is appropriate for a given film is arrived at in the collaboration of film maker and composer.
Perhaps you were wanting to understand How composers work at arriving at underscoring which seems to perfectly match the action - technical considerations such as that.
Your question also made me think of how in this day and age where there is software developed for most any endeavor you can name, from writing music, to designing houses, developing graphic art etc - we can sometimes think that there will be a program which will magically make us able to be brilliant in a given area, with the software helping us to skip the learning process. And of course, that's a fantasy - thank heavens. Software can provide us with great tools, but the best work generated with the help of software is from people of some knowledge in a given field.
If you did mean you're a beginner at composition - I would suggest that the first thing to focus on is writing music itself, without jumping to what genre it's written in or in what way it could be used.
Take a look at the interactive courses Nikolas pointed out which are right here at the Garritan Forum.