I realized In my first airsoft instructable I had forgotten a step on how to load an airsoft magazine. So here is how to load one.
Step 1: Pull Down the Spring
Pull down the spring on the side until it clicks in. Hold it down just to be safe.
Step 2: Push the Thing Down
Then you want to push the on top down.
Step 3: Insert BB's
I isn't have any BB's to show this, so just put them Into the top hole, then let go of the Button, and you should be good. If you don't close the thing on top, then all your BB's will fly out and you will lose a bunch. I learned that the hard way. Three times.