Control power of a eletric motor with arduino

Hello, how do I control the power of an electric motor using a relay module and an arduino? The motor is 110 watts.

A relay is an on/off device. Using it you can only turn the power to a motor on and off. Is that what you want to do ?

Do you have a relay ? If so, please provide a link to it.
Do you have a motor ? If so what voltage and current does it require to run ? Please provide a link to it.