When the player has completed this phase the "Prebuild Complete" button should be pressed to advance to the actual landing site where the units and structures have been tightbeamed.  When the game begins, the player should immediately send the Hovertrucks off to mine some lava.  There is a lava pit just east of the landing site and next to that is an elevator to the underground level! The player should send their Drilltruck into this elevator and then switch layers to navigate it underground.