Can someone Help me with this?

Question

im trying to write a simple program to enter a password into a text field of another program. I could use a macro to do it, but well i just want to write it myself, especially since i havent worked with any programming in many months. In anycase i just dont know how to get the Pointer to the text field. How do i find it? I have the pointer to the program (main window), but what to do after that point i have no idea. Please help me with this, its going to be bugging me ALL day lol thanks alot for your time ~jesse