Bests & Worsts Reviews from Amazon

Got this item today. I ordered it for the guest room because I have the full sized version as well and it affords a lot of under bed storage. However, i took it out of the box and assembled (very simple) to find it doesn’t sit flat. The 4 outside legs are flat on the floor but the middle two raise up, not touching the floor. I can’t tell anything I did incorrectly on the assembly. Bummer!