Can anyone give me a few tips before I attempt this? I have a "device only" Verizon 5S purchased fom an Apple retail store. I have a nano SIM purchased separately from a T-Mobile retail store. Is it just a matter of inserting the nano SIM into the iPhone's SIM card slot and connecting to iTunes? I'm just looking to establish a brand new T-Mobile account for this phone. I'm planning on purchasing their 2.5GB $60 plan. Thanks!