It is not easy to assemble the drawers through the glue they provide and we fortify the drawers with our own screws.  Get a better glue or insert the screws to fortify the drawers.  
The instruction on the manual is not clear and leads us to the wrong direction.  
Please be cautious that the distance of the holes on both longest side boards is not correct and that makes the drawers unclosable.  We need to remove the drawers and punch the holes based on the re-measurement. 
Due to the wrong instruction, it took us 8 hours to complete the installation.  One of us is a carpenter.

The quality of the material is not that good, but it is still doable for that price.  The completed closet does look nice and triples the space.
I recommend it to the people who are handy and patient.