Lay the duvet cover flat with the opening at the bottom (or locate the ties/fasteners inside).
Turn the duvet cover inside out.
Insert the duvet into the cover.
Grasp the corners of the duvet and align them with the corners of the cover.
Shake and push the duvet into the cover until the corners are fully seated.
Reach inside and pull the cover corners over the duvet corners.
Close the cover opening using the zipper/buttons/snap tabs.
Turn the cover right-side out.
Attach internal ties to the duvet loops (if present) and secure.
Smooth and adjust the duvet so it sits evenly inside the cover.