LG G5400 User Manual page 17

To connect the travel adapter to the phone, you must have installed
the battery.
16
Position the lugs on the bottom of
the battery into the retaining holder.
Then push to the half of the battery
into position.
With the arrow facing you as shown
in the diagram push the plug on the
battery adapter into the socket on
the bottom of the phone until it
clicks into place.
Connect the other end of the travel
adapter to the mains socket.
Use only the included packing
charger.