The goal of this puzzle is to make three cubes from the given pieces.
See Build Instructions here: https://www.instructables.com/id/Three-Cube-Puzzle/
For the print, all the parts are the same. You will need to print 3 pieces. Two STL files are included. For the magnets, one has a 5mm hole while the other is slightly oversized (5.1mm). I would try the 5mm first. This worked for me but all printers are different. If the 5mm is too loose, use a little epoxy before inserting the magnets.
Magnets link: https://amzn.to/2GNeK1c
The red, green and yellow picture shows the solution. Note that you might need to shuffle the parts around due to magnet polarity.
Please let me know if you have any questions!