Mine came with no instructions so I made sure to check the product info after receiving it.  This is a fabulous mattress and in my opinion, the best thing to do is give it adequate time to expand before sleeping on it.  I know several people who slept on it the first night and were complaining it was lumpy or uneven within 6mo.  The product info recommended leaving it for 72hrs, I only gave it 48hrs because I couldn’t face a 3rd night on the couch but the difference is significant.