We followed the directions for opening and let the topper open on its own. In a few hours it had unrolled and started to flatten out. We didn't have space to let the King topper open in another room so we let it air out in our room. It does smell industrial and this goes away in a few days. If you can air out in another unoccupied room, I would recommend this. Also it did seem hot at first (maybe we should have waited a few more days before sleeping on). I have to say now it is very comfortable and makes for a good nights sleep. It does add a full 4 inches to your mattress and makes it a challenge to keep the sheets on (maybe time for some new ones!) I would recommend this topper, the price was very good compared to those in major stores in our area.