It has 7 terminals. The 'sleeve' connects to the tag at the entry end of the socket, the one on the top side on your photograph.
Of the remaining ones, there will be three for the left channel and three for the right channel. The sleeve is common to both. One for each channel will be the connection to the plug when inserted, the other two will be a switch which is operated when a plug is inserted. The switched tags are for disconnecting the loudspeaker so they are silent when using headphones.
If in doubt, plug headphones in, wire the sleeve to one side of an audio source and wire the other side to each of the other pins to see which produces sound in each ear.
Brian.