Thanks for trying the game!
If you haven't figured it out yourself yet: H is the main interact key ;)
Yeah, that took a while to find, and Z and S for up and down is bizarre on a QWERTY keyboard. What layout are you working with?
The controls are explained on this page ;)
Walking around works with both the arrow keys, WASD and for people with an AZERTY keyboard (like mine), where A/Q, Z/W and more keys are swapped) that becomes ZQSD.