Use this instructional model and video to learn how to assemble the 6-piece burr puzzle. Once assembled, the trick is to slide “Piece 3” out to the side to unlock and remove Pieces 5 & 6.
See here for video on how to assemble: https://youtu.be/UcFXx5P6eX4
This model is part of the family of different “6-Piece Burr Puzzle” configurations. This is a “Level 1” design because one piece needs to be moved (“unlocked”) before you can begin to disassemble the puzzle. Disassembly is tricky, but reassembling is much harder!