How to get image from laptop to external monitor?

I have hooked up a monitor to my laptop. how do i get each screen to show a different image?

• I have hooked up a monitor to my laptop. how do i get each screen to show a different image? I was hoping to use my laptop screen to look at a excel spreadsheet and use the larger monitor screen to look another programme. I know this can be done but have no idea how. Have both screensshowing the same desktop how do i now get each screen showing separate programmes ??

• Answer:

  Press and hold the fn key (bottom left of the keyboard) and then there should be a picture on one of the F5 keys (usually F4) to change the projection mode (to extend), it looks like a box with a vertical line either side. If that doesn't work, right click on the desktop, click Screen Resolution and change the display type to Extend