Use the metal spudger to push out the lock of the battery compartment by putting the metal spudger between the kickstand and the plastic and applying a force upwards.

Be careful as applying to much force with the metal spudger could break the plastic covering. If you feel like the plastic is going to break, change the angle at which you use the metal spudger.

You can only use the metal spudger on the same side as the headphone jack. Using the metal spudger on the other side will give you no results.