Replacement instructions:
With the trigger removed from the receiver push the ejector pin and magazine release latch pin 1/3 of the way out starting from the bolt, hold open the side of the trigger. Pull out the current bolt hold open then slide in the Auto Bolt release. Push the two pins back through. Check if it functions correctly by depressing the portion close to the magazine release lever to see if the top side of the auto bolt release toggles up.
With the trigger removed from the receiver push the ejector pin and magazine release latch pin 1/3 of the way out starting from the bolt, hold open the side of the trigger. Pull out the current bolt hold open then slide in the Auto Bolt release. Push the two pins back through. Check if it functions correctly by depressing the portion close to the magazine release lever to see if the top side of the auto bolt release toggles up.