Taking off with huey uh-1

i am new to flying helicopters and i watched many videos on the operation of the huey uh-1. When i start up the bird i put i slight left rear cytick and gradually raise collective. Once i lift up the huey turns far to the right and the huey rolls over. What am i doing wrong?

Are you making anti-torque inputs? These would typically be made with pedals or the twist on your joystick, assuming you have either

Which sim?

Sounds like you are not putting in pedal inputs to counter the torque created by the gearbox driving the rotors.
As you increase collective, so should your left pedal input on the Huey.