Where to mount the extruder on Rostock Mini

I am nearly finished building my 3dprinterczar Rostock delta mini pro, but have no clue how both the acrylic build plate, the arduino/ramps ánd the extruder should be fixed to the construction bottom plate.
The build manual stops before that point is reached.

Anyone has found a solution that uses any of the remaining holes in the bottom acrylic plate ?

Thomas