you'll find the larger box isn't fitted due to kerf and bad design
but the small one sides are fit to each other all you need to do is assemble it with your hand and take care not to press so hard so you don't break the box
here's what I did :
1st mistake:I drew even number of 5mm taps without using parameters , and repeated the face without creating new components so editing one face will edit them all ,
correction : I should draw odd number of taps 3 mm each as the used plywood is 3 mm thickness.
2nd mistake :
taps and holes are the same widthe and that's a big mistake due to kerf clearence
correction is taps larger than holes
don't add any taps to the faces just subtract andtapswill appear make sure of the kerf according to the used speed and work limitations
-How did I come out with this result ?
I draw a single face and a very simple indeed because complexing it didn't help.
Using parameters is a success key since yu have repeated too many dimension like ( tap width +kerf ) for taps and tap width-kerf ) for holes and (major lenght )of the cube .
copied it 5 times and created all of them as new components by right click bodies on the left side of drawing window and selectin new components.
after that I saved it as .dxf file by right click sketches and selecting it .