How to change carriers on Unlocked iPhone 5?

I think I unlocked my iPhone 5. I'm from USA and am in Israel currently. I'm trying to select one of the carriers that are listed, but when I do, I still get no service. How can I select a carrier so I can use service?

If it IS unlocked, you should just insert your (micro or nano, I forget) SIM card into it, and it might work. If not, you either didn't unlock it, or the frequency bands you purchased it with aren't available in the area you're trying to use it in. And by the way, you can't just click which carrier to use. You have to buy a plan and get a SIM card first. Most likely, you bought it from a carrier in the US, and since we use different bands for service here, it's not picking anything up.