This part is basically the same as hackpad, so layout, then routing, except for the mousebites. So in this section I will give some tips for laying out a split keyboard.
Here is my final pcb:

#If the two halves are symmetrical
#Mirror the edge cuts
- Then you should make the edge.cuts for one half, select all the
edge.cuts, right click, and
flip horizontal, and now you have two symmetrical edge.cuts.
#Mousebites layout
#Place the mousebites
-
You should find two flat sides of your two PCBs, place the mousebites there, and edit the edge cuts so it matches the mousebites footprint template:
