I just got my hands on a previously owned Apple 1st Generation Iphone. Its still locked. However I have ATT. I dont want to change any contracts, or pay extra money. How do I use it with my current sim card? should i just take the sim i have and put it in, then use ziphone or something? And if so can someone please give me a step by step, im extreamly noobish and dumb, just a quick step by step would be great!