Choose the screen resolution you want for each monitor, and select which will be your primary monitor and which will be your secondary. The primary monitor will run most programs when you first open them.
Certain computers give you the option to use your monitors as a single, long desktop instead of two separate desktops. If available, the screen resolution menu will have a horizontal desktop option.
Move a program or game onto the second monitor by minimizing it and dragging the window across the screen from the first monitor onto the second. The mouse will jump from the edge of one monitor screen onto the next.