Why can't I do anything on the second monitor?

Question

Monitors

Windows 8, laptop - dell inspiron 1545 late, insert vga connector, cord, select the function to expand the screen, the screen is distributed to the monitor and the laptop everything seems to be correct, BUT how to switch to the monitor screen? that is, I can only work with a laptop and I don’t know how to switch to a monitor, who can tell me?