Using a scanner is as simple as installing the included software and plugging the unit into the USB and opening the software. The Canon scanners I work with are easy to use. Contact Canon support if you have specific questiions about one of their scanners.
If you plan on making a living doing this, I suggest you get one that can scan slides and negatives as well and make sure it has the required accessories to do the job.
I agree with badge about getting a Canon, they make a good product with good software.