How do I get the screen bright on my Winbook laptop?

I booted my brother's laptop and could hear it working, but I couldn't see the pictures on the screen. I changed it's position and could slightly see the pictures. Please tell me how to .. brighten them.How do I get the screen bright on my Winbook laptop?
it could be that the back light is not working.but there should be a key called function (it's the lower left key) and 2 keys with a symbol of a sun looking thing .hold down the function key and the one key that looks like a full sun. good luck......ps if it doesn't work try hooking up a PC monitor to it.