To smoothly assemble, it helps to pre-fold the creases.

1. Insert part ①

2. Shape and fold up to the center position.

3. Close part ②
4. before closing part ③.

5. Insert while covering the outside.

6. To facilitate easy opening, close the lid with a semicircular opening first.
7. Finally, close the outer lid to complete the assembly.
Since it can be reopened, it's safer to insert the bottle last.