Can someone tell me how to decode bmw with my obd scanner?

I got the bmw x3 2.5i cheap but it only had one key with it but long story short my 5yr old was playing with my keys and other stuff next to my chair and he most of took my key outside or ate it because ive looked for a month to find my key and I don't want to have it tow to the bmw dealership to reprogram it plus I don't want to spend around 200$ for them to do it when. They can cut me a new key that is factory that unlocks the door and start same key. So what is the best way to do it because I only give 230$ for the bmw x3 nothing else is wrong with but I just need another key made for itirs… Read complete