Key Impressioning Mould

You need to file down the edges (i marked them blue in one of the pics) so you can put it together and then you need to insert some kind of rod, i used a 2mm thick steel rod, the holes in the model have in theory a 2.8mm diameter (i wanted to use a nail i had laying around, my printer kind of messed it up)
Also u need to flip it 90 degrees because i used fusion360