Before beginning, please make sure that you are using the correct-sized SIM Card for your iPhone or Android.
To Insert a SIM Card Into an iPhone:
Stick a pin into the slot on the side of your iPhone. This should cause the SIM Card tray to pop out. Your SIM Card should be placed here, and re-inserted back into the phone.
To Insert a SIM Card Into an Android:
Remove the back plate from your Android phone, and locate the SIM Card tray. Slide the SIM Card into the tray, and securely reattach your phone's back plate.