It's a really simple process. With the slide off, push down on the plastic t-block with a punch or even toothpick. Then, slide the take down bar out either side. Gently, let up on the t-block and then remove with tweezers. Be careful to not lose the spring. Move the spring to the new block and gently put it in place with tweezers. Push back down on it again and then slide the take down bar back in. Let up on the new steel t-block and Bob's your uncle! It is easily the fastest upgrade I've done in a long, long time.