U3415W, sleep mode, switches

I have recently bought a Dell U3415Wb from eBay. It was advertised as an ex-display model, I bought it because I have always wanted a decent monitor. The problem I have is that I cannot seem to stop it from going into sleep mode and also the manual from the DELL website does not really correspond with the actual monitor. I cannot seem to find all the switches that are shown in the manual but are not on the actual monitor. Any help would be greatly appreciated.