Which circuit should i use for Ac voltage Controlling ?

I would like to design a circuit which can control the light intensity controller for Big size Light Chandeliers, so if anyone can help me with this and telling me what to do ?

Use a triac. If you don't know what a triac is, don't do this.

what about diac triac power control circuit, i mean how can i decide the values for each components and how to simulate this circuit ?