At the outside Telephone Box, install the suppressor inside the telephone box or let it hang by the wires outside the box in a wet proof location.
Connect the large GREEN wire to the Telephone Ground Terminal or any other good ground. Sometimes the electrical ground is nearby and you can connect to it.
Each Telephone Line has two wires, usually red and green or black and yellow.
There are 4 smaller wires on the suppressor, one pair for one phone line and the other to the other phone line (if you have a second line).
There is no polarity to the suppressor wires, you can connect any of the wires to the phone lines and the suppressor will work as intended.
Keep the wires as short as possible and avoid sharp bends and kinks.