Painless Suicide Methods Needed Asap

I heard of using nitrogen as a painless way to die. Is this right? If so, can anyone please share the steps on how to die using this? What particular nitrogen do I buy? Where can I buy it? I also heard of a website/s that advocates and provides step by step procedures on suicide. Can anyone also share the link? Also, any inputs on painless suicide methods would be much appreciated. Any messages on talking me out of killing myself will be ignored.