As the design of the headband is ambipolar, which side of it is designated as the left or right side does not matter.

Before inserting the drivers back into the headband, make sure the metal place holders that secure driver length are correctly inserted at the start of the interface. The small spheroidal convex indentation of this piece should have the convex (protruding) side facing outwards which will interface with the concave indentations on the drivers.

To verify that the metal placeholders are properly installed: if the inner part of the Interface that attaches the headstrap to the headband can be closed with ease (must be actively held together), and the driver being inserted correctly locks in place, the metal place holders have been correctly installed and you may proceed onwards.

Make sure the metal fasteners have the correct polarity, either L or R, facing on the inside.

After ensuring that the metal fasteners are facing the correct direction, slide the drivers back into the headband and firmly press closed the Interface as shown in the video.