Put your thumb and forefinger on both sides of the triangle and throw GENTLY so it glides. Have fun!
I found this paper airplane on a website (I can't remember for the life of me what it was) but it's easy to make and it can take some small mistakes in folding. I couldn't find any just like it on Instructables but if you find one like it, send me the link. Also, if you mod it, tell me what you did, because I want to try it out. This plane works so well you can even use three hole paper, and it will still fly! (Me and my friend found this out during band class when there was a substitute. We got bored and made some.)