Standard Procedure Battery Replacement

With the transmitter buttons facing down, use a coin to pry the two halves of the transmitter apart. Make sure not to damage the rubber gasket during separation of the housing halves.
Remove the battery from the transmitter back housing holder.
Replace the batteries. Avoid touching the new batteries with your fingers, Skin oils may cause battery deterioration. If you touch a battery, clean it off with rubbing alcohol.
To assemble the transmitter case, snap the two halves together.