How do you mean they have no measurements? The unit is mm I think.
I have no idea XD The guy is asking me for the thickness and the length of each part and I have no idea what to say XD
The measurements are in mm.
He might be confused about the thickness of the material you want to use, as those aren't specified in the file.
The thickness of the layers required would be 3mm for top and bottom layers, and 4.5mm for the middle three layers, or in inches:
1/8"
3/16"
3/16" <--- mounting plate
3/16"
1/8"
keep in mind that most acrylic sheets being sold has a +/- 10% variance, so you could get away with a slight difference sometimes depending on where you get your plates cut.