Just got my new cats eye taillight and am trying to hook it up. However the wires on the bike and the wires on the light dont match up (bike;black white brown)(light; black red yellow) I have tried all 6 possible combos and none seem to make the light work right, With some combos the brake light is on only with others boke tail and brake light are on all the time and still with other combos no brake light at all. I thaught i had it, had the taillight on and brake light worked with front brake but when i tried the rear brake the brake light came on and stayed that way even when i let of the pedal. Please help!

that helps a lot but i still dont know which is which on the taillight,

It didn't come with a wiring diagram/list/instructions?

in the land of normal:
black = ground.
my guess would be:
red = brake light
yellow = tail light

The brighter of the 2 lights is the brake light.