Ok... I'm not really a canon user, my gears nikon/minolta but the question is a bit weird.
The 9 focus points in the simplest terms basically 9 sensor points which are used to determine the best focus to use for the photo. I'm not entirely sure if canon do the same as nikon where you can manually select a point to focus on but if it does then all you're doing is overriding the automatic program to focus on that one point.
As to focusing manually, yeah it's easy although it's not as easy as a pure manual focus ring (pretty sure this isn't on a canon) due to it not having the 'manual focus ring' in the middle of the screen so it's more by eye. You will of course need to set the lens to manual instead of af.
However I'm actually thinking what you're more interested in is aperture settings which are used to 'selectively focus' parts of the image. Larger apertures (smaller f numbers) allow for a shallow focus range while the smaller apertures (larger f numbers) give a deeper focus range (ie more is in focus). Generally speaking you'd be using a larger f number on landscapes so more is in focus while a smaller f number would be used on something like a portrait so the background is softer and out of focus. Look into depth of field for more info.
This does have an impact on shutter speeds and it can make some shots take considerable longer to 'snap' depending on your choice of aperture, so tripod/monopod is highly recommended. Automatic exposure (or dial preset) in conjunction with the 9 points of focus will pick the best option for you but you can manually assign both the aperture and the shutterspeeds via the m part of the dial (using the dials), if you set s, you set the shutter speed and then the camera auto selects the best aperture. Setting a allows you to preset the aperture (see above for reasons) and the camera then selects the best shutter speed, this can result in slow photos which are prone for camera shake.
But like squiddy says, can we get some more info please
And a sidenote (not a dig or anything): this is part of the problem with going straight in with an af camera, it's very convenient for people to get going quickly, which is great for most people, but a lot of the, I'll call it fundamentals of the process behind the taking of the picture are missed out, even more so now with the digital age where if it's not right you just delete it and try again. I started photography with 35mm film and a fully manual camera (even know how to develop film, not that I do it often) and these fundamentals were essential to getting the 'best' picture and being that it was film not digital, I didn't have the viewfinder previews or anything so if it was wrong then it was wrong till I got it developed. It's paid dividends because I feel it's made my af photography (I still go manual if needed) better and it's also helped a LOT with composition and lighting on my 3d renderings
EDIT: Squiddy, I may have found a forum bug.... I do an edit and click save changes and the 'window' doesn't go back to the forum, it's just stays in the edit mode after the green dots are finished. Firefox, latest build