how do you scan something in the computer?
You must have a scanner attached to the computer, as well as the scanning program installed. Sometimes people buy scanners separately; sometimes they buy them as an all-in-one machine (printer and scanner and fax and copier -- or some combination). In any case, you must have the software for that machine installed on the computer.
THEN you can scan something.
Follow the directions in the machine's manual or go into the scanner's program on the computer and use the Help section (press the F1 key to get help).
http://www.google.com/search?q=how+to+scan&rls=com.microsoft:*:IE-SearchBox&ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7ADBF_en