Ratchet straps -- used to hold down anything from an ATV to lumber -- can be a little confusing to operate. However, with a bit of practice you will not need a picture to show you how to unlock the strap. Just as it took a little patience when learning how to get the strap to ratchet tight, you will have no issues releasing that tension once you've done it successfully once or twice.
Pull the handle of the ratchet strap into the open position. The handle will open slightly less than half way.
Locate the spring-loaded locking mechanism in-between both handles. Pull the lock towards the back of the handle and away from the rolled up nylon strap. This releases pressure on the ratcheting handle.
Pull back on the handle while still holding the lock open. The handle will open the rest of the way and lock into place.
Pull on the ratcheting mechanism to uncoil and loosen the nylon strap.