New user

[fiat]

Hi, I will be a first-time cellphone/smartphone/iphone user when I receive my new full price unlocked iphone 5s (with T-M sim card installed) from Apple in Oct. So here is my basic question: How do I start to use my new iphone? I plan to purchase pre-paid plan ($100 for 1000 min talking only) from T-M and I do not have any cellphone account now (no number to transfer). Can anyone help me to accomplish this? How much will be any extra cost except the plan fee? I plan to use only wifi for data transfer and I have mac with itunes 11, internet access, home wifi, etc. Thanks