Displays are display port, sometimes HDMI, not thunderbolt. Display port also runs over TB and uses the same connection, but is a bit different.
In order to run two displays on a single TB port, one display must be a TB display, like the apple thunderbolt display. Otherwise you must grab a $$$ TB expansion chassis and a Video card that in turn drives multiple displays. You can daisy chain a thunderbolt device (like an Apple Display) with a display port device, but the display port device must be at the far end of the chain.