Your SIM and battery must be inserted before you can use your mobile phone.
- To remove the back cover, you must turn the back of your Samsung Galaxy S3 towards you.
- Hold on the top of the back cover and remove it.
- Place the SIM by sliding it in the slot located below the battery holder.
- To insert the battery, you just have to match the battery contacts with the contacts in your mobile phone, and press the battery into place.
- Place the back cover on your mobile phone, bottom first, and press it into place.