Windshield repair kit

I bought this because I had a small crack in my windshield and I still don't know why. My car was parked and maybe it was a kid or a rock fell on it.. I'll never know. I was told the small crack will spread larger and larger and I honestly didn't have enough money to buy a new windshield, so I bought this to try and repair it. I didn't get a chance to because I totaled my car and broke my back and foot. Its just ironic because before my accident I bought everything to hook up my car. LOL and then I get everything delivered in the mail. Well, anyway it's here for the taking now. That's why it's never been used.