-PowermacG5
I'll do my best...
First off, just get a book for it from Crown/Barnes/Borders.
The first thing you'll need to know is what you are looking at when you first launch.
You have the Browser, this is where your media is stored and made ready for use - iMovie has this, it's where your clips are stored. However with FCP/E you can store more than just video, you can store Pictures, audio files, graphics, and multilayer Photoshop .psd files (really good PhotoShop integration here).
The next is the timeline, again, like iMovie, but you can have more than one video track - ergo FCP/E's designation as a Digital Non-Linear Editor. Like Photoshop the Higher layers are on top, and knowing this will help you with transitions, and compositing.
The Viewer is how you preview and get your clips ready for insertion into the timeline. Here you will be introduced the concept of IN and OUT points. Every Clip has to have a IN point - the point where you wish inside the clip to start in the final edit. The Timeline must have an IN point as well - the point where the clip starts in the Timeline.
Think anchors.
There only needs to be one OUT point. If you place the OUT point in the clip, the clip in the Timelinewill end when the clip hits that point - the clip will dictate to the Timelineits length.
If you place the OUT point in the Timeline, the clip will end at that point - the clip length is dictated by the Timeline. Handy for filling a gap in your timeline.
These points are set with the "I" and "O" keys on your keyboard.
But, of course, before you can begin editing with In and OUT points, you need to capture. File to "Log and Capture" with your deck connected (camera). Use the preview controls to find your clip. And, at the point where you wish the clip to be captured, set and IN point (ah-HA!), and a concurrent OUT point where you want to end the capture. You can then, in the Capture section, hit "Clip" which will make FCP capture that clip you just logged, or you can hit "Log Clip" which will save the clips inpoints for future capture - this is really cool as you can rack up a bunch of captures, then hit one button for a mass capture - and go get a coffee.
I skipped ofer the naming of clips in loggin, and a few other details, but this should be enough for you to get started.