Sometimes the screw posts can be stubborn. We suggest you use your thumb to push into the “T” side of the screw post while using a flat-head screw driver to unscrew the opposite side of the screw post. Be sure to turn the screw driver in a counter-clockwise direction (to the left) to unscrew.
You need to push the two ends of the screw post together to create the friction to unscrew them – otherwise you’ll end up turning the entire post and not unscrewing them. If you have one of those rubber kitchen gadgets used to open jars, that usually does the trick for more stubborn screw posts.