Advice needed...

I have this bathroom light switch which has three connections: S1, S2
and COM.

My ohm meter shows that when the light switch cord is pulled, a
connection is made between COM and S1. When you pull the cord again,
it changes to a connection between COM and S2. Pull it again and it
goes back to a connection between COM and S1.

The cable from the mains has a red a black and a bare copper earth.
The cable to the light is the same type.

What is the correct way to wire up the switch?

Thank you.

Al Deveron