Same problem everyone else has had..  Panels are pre-drilled incorrectly (or panel assembled incorrectly at factory) so plastic brackets don’t line up.  Had to go to hardware store to buy some “L” brackets to finish the job.  Barrel locking fittings are a “soft metal” and split easily if over tightened.  Cheap particle board wood..  Had a blemish on the underside of the main desk panel.  Overall I got it together and it looks good.  Just took some “handyman” work and extra parts to get it together.  See images.