This page shows the continuation of the paper gift box from Step 11.
Step 11: Take the point where the triangle fold ends and bend it inwards.
Step 12: Make a "V" shaped bend as we have shown in the below image.
Step 13: Similarly do it in the other side too.
Step 14: Bring the open end towards inside.
Step 15: Fold it inward to touch the base.
Step 16: Take the other side and make the same "V" bend in the both the ends.
Step 17: Fold the open ends towards inside.
Step 18: Your gift box is almost done.
Step 19: Use glue and paste the open corners.
Step 20: Make an other gift box in different size and join the open ends.