Make sure you've installed the H/F Series ASIO Driver from the Zoom website.
In Studio One, in Audio Setup, make sure to choose Zoom ASIO as your device.
If you've done that but still can't hear anything that's because your Audio I/O is not setup in your Song Setup.
Then in your Song Setup, set up your Audio Inputs and Outputs according to how you wish to use your H6 with Studio One.
Watch this video on how to setup your Audio I/O in Studio One. This does not specifically cite your device, however the principal applies.