Controlling Fan Speed in Postman

Greetings again!
I wanted to know how to control the speed of a 3 speed fan. I was previously told how to control a dimmer which worked great. But sadly, the same Post Body doesnot apply to 3 speed fan since it has a seperate capability called fanSpeed.

I’ve tried the code below and many other strings as commands (that I could’ve guessed).

{
"commands": [
    {
        "component": "main",
        "capability": "fanSpeed",
        "command": "setFan",
        "arguments" : [2]
    }
]
}

Thanks!

setFanSpeed