Wow, sounds like you could use some help. Here is a page with some great basic video tutorials for you to watch.
http://files.lynda.com/files/finalcutstudio/index.html?utm_source=apple_fcs&utm_medium=partner&utm_content=apple_fcs&utm_campaign=apple_fcs
They're for Final Cut Pro, but it works basically the same as Final Cut Express. Here's a quick summary in answer to your questions, in order of the workflow.
The browser is where you'll have all the elements of your project. When you import video, music, still images, graphics or anything else, it will end up in the Browser.
Video you import into FC is referred to as Clips, referring back to the days when you had to physically cut out the pieces of film you wanted to use with a razor. A string of clips assembled together is called a Sequence, and by default, a new, blank sequence is already there in the Browser when you start a new project. You can have as many sequences as you want. For instance, you might have slightly different versions of a sequence meant for different things, or you might want to work on a duplicate version of a sequence in case you make mistakes and want to start again from an earlier version. To rename a Sequence, click on its title (NOT its icon) and type in a new name.
A sequence is nothing until you have some video clips in it. You do this by double clicking on a clip's ICON (not its name) in the Browser, which will open it up in the Viewer window. Here is where you can mark which portions of the clip you want to use. All you need to do is park the Playhead (the moving vertical line in the scrubber bar at the bottom of the Viewer window with the tiny yellow triangle on top of it) and press the "I" key. "I" stands for In Point. The In Point can be moved by dragging it or by parking the playhead in a new location and pressing "I" again. It can be deleted by pressing Option-I. Now move the Playhead to the point in the clip where you want it to end and press the "O" key. This creates the Out Point, which can be moved like the In point and deleted by pressing Option-O.
Now you can add the clip to your sequence. Do this by clicking and holding in the middle of the Viewer image area and dragging it down into the Timeline at the bottom of the FC interface and dropping it into position. You can also drag the Viewer clip over to the Canvas window, where some overlays will appear. One of the overlays is "Overwrite". Dropping the clip onto this overlay will add the clip to the Timeline, overwriting anything else that might be in that area already. The clip will be added wherever the playhead is parked in the timeline, so first make sure that the timeline playhead is exactly where you want the clip to be added. Once a clip is edited into the sequence, the playhead moves to the end of the clip, ready for the next edit. If you want to use a different section of the same clip, just keep it in the Viewer and create new In and Out points and add it to the sequence the same way. Don't worry; the first portion of the clip already in the timeline will retain its In and Out points , and you can do this as many times as you want. You can also drag a clip within the timeline left or right and even up or down to move it exactly where you want it.
The Canvas and the Timeline are connected, meaning that the Timeline is a graphical representation of your project, and the Canvas shows you how your project actually looks and flows. Notice that the Timeline and Canvas playheads move simultaneously.
Keep adding clips until you have a rough assembly of your project in the timeline. you can refine your edit points from within the timeline too, but I don't want to get sidetracked here. There are blade tools and other tools that can help you trim the clips in the timeline with more precision.
Once you have several clips in the Timeline, you can add transitions. To do this, click on the Effects tab in the Browser and reveal the Video Transitions list. You can drag any of the transitions directly into the Timeline. Drop the transition directly on the edit point between two clips and that's it. You can also select an edit point by clicking on it once, then choose a transition from the Effects menu at the top of the screen. Depending on what you want and how much available footage there is, you can center the transition on the edit point, or have it begin or end on the edit point. You can also double click the transition and it will open up in the Viewer window where you can alter its duration and other properties.
The most important thing to remember is that FC is a non-destructive editing system. That means the video clips you work with are NOT the actual video files themselves. They are reference clips, so no matter how many times you need to use a clip, no matter how you cut it up, no matter what effects you add to it, the original movie file is untouched and unharmed on your hard drive.