Attach the aluminium profile to three sides of the wooden board.
Then fasten the Plexiglas panel with the transparent adhesive tape.
The wooden board and the Plexiglas panel have to be about 2 mm apart from each other (the magnets are 2 mm thick), so the magnets can be inserted without being able to turn.
Now push one magnet after the other between the two plates.
This way all the magnets are equally poled and repel from each other.
Finally, finish the frame with another aluminium profile, so the magnets stay in the frame.
Now the frame is done! It is fun to observe the reaction of the small magnets when you move the frame or bring stronger magnets (in this case a huge magnet S-45-30-N) in the picture from the outside.