The tabs fit outside the metal magazine body and fit into a slot on either side of the floorplate. I took mine apart just to see how it works and goes together. I didn't have any problem removing the floorplate and spring. I used a small diameter flat bottomed punch to press down on the release position, which moves the spring floor plate underneath the plastic floor plate that secures everything inside the mag. Putting things back together was a bear the first time!! I finally put my mag body in my vise (with protective vice jaw covers) taking great care not to tighten the vise enough to bend the mag body ... just enough to hold it fairly securely in place to allow me to use both hands to replace the other parts. The spring floor plate fits entirely inside the mag body, and it's tricky to hold it in place while sliding on the plastic bottom plate. The front of the spring floor plate will tend to rise upward as you slide the bottom portion in place as the hump on the back of that bottom portion requires you to move your thumb toward the rear of the mag body. Do not allow the spring floor plate to move backward as you slide the bottom plate into position and take care not to move the spring floor plate forward or it will not seat inside the mag body. It will hang up on the front edge of the mag body. When the spring floorplate rises at the front, those two tabs will angle forward but if you do not allow the floorplate to move forward or backward as you slide the bottom plate rearward, those tabs will be pressed rearward and snap into place. It also helps if you will take your punch and press downward slightly on the spring floor plate to help hold down the front of that plate as your slide the bottom plate into place. I don't think I could have done this while just holding the mag in my two hands. Using the vice for a third hand made the difference. Good Luck!!!
I must have got it back together right though, since it works fine.
