The Blue2 has two built-in switches, one white and one orange. These switches can be used to active two independent functions in any of the six available modes. You may also opt to connect an alternative switch to the Blue2. This can be done by using either (or both) of the 3.5mm connections on the back of the Blue2.
Please note: any switch that is connect to the Blue2 will emulate the same function as the built-in switches. They cannot be assigned independent functions.