A couple of issues here:
- the area which needs to be surfaced isn’t 32 x 32 — suggest you use the rapid position points to work out where the machine can move to: https://www.shapeoko.com/wiki/index.php/SO3_Function_Test#Distance_of_travel
- once you have the desired geometry worked up in relation to the movement area of the machine (see: Notes on rapid positions and wasteboard leveling for a sample file for an XL) you’ll need to create a suitable pocket toolpath — just have it cut 0.1mm
- having a wasteboard which is only the working area will result in an island which is awkward to clamp to.
Retract height is the height to which the machine will retract in-between passes — see: http://docs.carbide3d.com/assembly/carbidecreate/video-tutorials/#toolpaths for a discussion of this and https://www.shapeoko.com/wiki/index.php/Glossary for terminology