Get the MB manual, then go to page 16. In the section 9) D_LED1/D_LED2 (Digital LED Strip Headers). Because the Aorus X470 ultra gaming does not have the 3-pin A-RGB header, try to use that VDG connector instead. But make sure you set the right jumper for your 5V VDG, don't mess it up with the 12V. Check the same page (page16) the 10) section Power Select Jumpers.
You can double check it out by yourself, make sure anything is right befroe you plug it in, because I don't have exactly MB and PSU, if you don't do it right you will kill the header or the MB.