You don't pull the slide FORWARD. Pull the slide slightly to the rear, just enough to relieve the pressure on the locking bar.
The easiest way (I would say do it like you do your Glock, but if you had a Glock, we likely would not be having this conversation) is to (assuming you are right handed) place right hand thumb just under the beavertail, and close your hand so that the four fingers of the right hand are wrapped over the top of the slide. Then, with your left hand, reach up under the dust cover, cupping your hand around the bottom of the dust cover and frame so that, simultaneously, your left hand thumb is on the end of the locking bar on the left hand side of the pistol, and your right hand middle finger is on the end of the locking bar on the right hand side of the pistol. Then, "close" your right hand enough to cause the slide to retract just enough to relieve the pressure on the locking bar while at the same time pulling down on both sides of the locking bar AT THE SAME TIME with the thumb and middle finger of the left hand. Once you have the locking bar pulled down on both sides, release your right hand grip, and allow the slide to go forward. Make sure you do not allow it to slide off onto the floor or hard surface. The locking bar is one piece which protrudes slightly on both sides of the pistol. The idea is to pull both ends of it down at the same time. I hope that helps.
I STRONGLY recommend against extended locking bars as mentioned in posts above, as they can interfere with proper holstering.
