Tower ECT1250, two S2725H, setup as extended?

I bought the tower and the two S2725H and spent two days trying to hook up the monitors to get an extended desktop where I can look up info on one monitor and type my resulsts on the other. The same as I would do for a tutorial with graphics and then doing the tutorial on the other monitor. Nothing is working so I know it has to be a simple hookup question but evidently I am doing it wrong? Can anyone help me set up the two S2725H extended?