Your switch may be different to the description below.
(650 export)
Also the colours may have faded.
Blue or blue/? wires are normally lighting.
Get a meter and check the connections AND colours.
The BLUE wire is the dip switch.
It will be either connected to the blue/white (main beam) or blue/red (dipped light) depending on whether the switch is up or down
This is the right-hand switch assembly, because it contains the front brake switch.
The WHITE goes to both of the push-buttons via an internal link, and also to the front brake switch...[the lever]
The BROWN is the other front-brake switch connection.
One button is the headlamp flash, so with the meter the white connects to blue/white when pushed.
The other button is the horn, purple/black.
Hence, when pushed the white connects to the purple/black.
This a lot easier to explain with the wiring diagram.