Since we started to distribute X-Sim Nano for the iPhone 5 (you can find it here) here are the steps to configure it.
It is very simple and normally just needs to insert your IMSI code once and that's it.
X-SIM NANO iPhone 5 iOS 6.1.4 Instructions
First of all, make sure you have deactivated the PIN request for the phone.
To disable the PIN request just go: Settings -> Phones -> SIM PIN (Select "Off") -> Enter 88888888 -> click "Done"
1. Insert SIM card (without PIN code) together with X-SIM
2. Phone will prompt "SIM LOCKED"
3. Click "Unlock"
4. Enter 7 digits IMSI (you can find it here)
5. Wait for signal
Just enjoy it.