How to activate my SIM card?

I just got my new phone (iPhone 5s) delivered to me today and it says 'no service' the other phone that I have is a blackberry but the SIM card is still on. I can use my blackberry…

Depending on your carrier, I believe you call the service number and let them know they can activate the phone.

This can be done from your old phone provided the account is still active but a few providers allow service calls on the new phone to activate

Depends on your network. Call them up, or look at the delivery note with your package