how do windows applications work?

i am trying to make a simple application that just types a random number in a search engine. i can do everything except for making the program do things on the screen. i tried making a windows application with visual c++ but its like learning a new language. can someone tell me how i can make a program just type something in for me?

 

You'll need to simulate key press and release.
http://msdn.microsoft.com/en-us/library/windows/desktop/dd375731(v=vs.85).aspx
Has the list of the Windows Virtual Key.