You are supposed to set the Main Reference point in the middle of the cross drilled on the Table Top. Not all machines have this cross, and on machines with a Conveyor Belt, the cross is hidden underneath the belt.
iPC comes with files to cut a template that can be used for establishing the Main Reference point position.
Produce the file with a knife-tool on some suitable paper-based material. Folding carton material is ideal.
Place the template as seen in pictures below. The template shall be positioned on the corner of the actual Table Top ("vacuum table"), flush with the Table Top edges in X and Y direction. Template as placed on an XL machine, inside the Stainless Steel cover along the Table Top: Template placed on an XN machine, inside the stainless steel cover along the the table top and inside the eloxated steel cover across the end:
Run the 'Set Main Reference point' wizard and use the cross in the template as your Main Reference position.