The MST Feature is supported by the OS therefor there is no driver needed for the MST Hubs.
Please make sure you have OS fully updated and also the latest Intel Graphics driver installed.
Please connect the MST Hub directly to the Surface and start with 1 screen connected to the hub. Make sure power is on the Hub and Screens. Wndows should see the screen, perhaps not “activated” yet or something like that. Go windows settings to check on resolution/frequency for the screen. Then do the next … it should indeed be as simple as that.