How i can put a lamp change the bright

Hi everyone,
I’m having a big problem with this project that i’m making. I have to controlling the bright of a lamp with a arduino but it goes wrong.
For doing this project i have one optocoupler(moc 3011), one arduino mega, one potentiometer 22k, one triac BT138, a 70W/230V lamp and 3 resistors. Does anyone knows what i can do to put this working.

Thanks for any honest help. :wink:

Arduino Phase Control

Thank you for the help ;D