I can not emphasize enough how important it is to organize your footage. It may not be a problem initially but over time it can become a mess. You are better off creating good habits initially and let that carry you though your editing with Final Cut.
When you open Final Cut, click on file, click on New and now you see three options Project, Event, Library. What do you click on first??
Let’s say you are making a two movies, “Caddyshack 3” and “Daniel’s Wedding” In this case you will create two libraries. One for each movie. Anytime you are working on a brand new video you should create a new library. When you create a library all of the subsequent footage that you import will be imported into that library. You can think about a library like a large storage container that holds your projects and events.
So you have already created a library called Caddyshack 3 and now you are going to create your first of two projects inside the library. The first project will be for the actual movie while the second project will be for the movie trailer. Since the trailer and movie projects are both related it should belong inside the same Caddyshake 3 library.
Think of events like scenes. Every scene should have its own event. I am currently working on a wedding video. In this case the bride getting ready is one event, the groom getting ready is another event, the first look is another event, the ceremony is one event. For every new scene in your video you should create a new event.