Need help with ice maker

I just bought a used refrigerator for my son but all the water lines under the refrigerator are disconnected. There are two white lines (one with a larger diameter hole than the other) and two grey lines (appear to be the same size). I cannot find a scematic to indicate how to connect them. Also, I notice that the line that connects to the water source on the back is grey. Can anyone tell me how to connect the lines and if the grey line is okay to hook the water source to? It seems to me that I should be able to connect them without necessitating a costly service visit. Thanks.