When you are ready to deflate your SUP removed the fin and simply release the valve and turn the stem down so it allows air to release (be careful since air rushes out rapidly when initially released). It helps to do this in a dry area so no water can get in the valve. As the air is being let out, start rolling the SUP from the back so the air can be pushed out to valve at the top. Once it is fully rolled up, use the strap to keep it tight and put it in it's carrying bag.