What do you want to use the controller for? Does it look something like this: https://www.amazon.com/StepOK-Controller-Splitter-Plastic-Lighting/dp/B0899VYB16/ref=sr_1_3?dchild=1&keywords=led+argb+sata&qid=1613380329&sr=8-3

If so it is a dumb controller that has some pre-set effects you can cycle through by pressing the button. You plug one end into power (SATA) and the other into your ARGB device (i.e. fan or light strip). You will have no software control if you use a device like this.

If you want to get the ARGB header to work that's a separate subject. You mention it's hooked up to your power supply. Does the power supply have an RGB fan? If you have other ARGB devices you want to hook up you can use a splitter like this: https://www.amazon.com/MICRO-CONNECTORS-3-Pin-Addressable-Splitter/dp/B07Z122WPT/ref=sr_1_6?dchild=1&keywords=argb+splitter&qid=1613380510&sr=8-6

You can get these much cheaper on other sites like aliexpress and probably eBay.

If you want help with what polychrome version to install I would need to know the exact motherboard model, because ASRock makes a ton of B450 boards (for example there are at least 8 versions of their B450 m-ATX boards).