Information on G-325R

Has anybody had to fill out this form yet. Im a canadian that frequently travels to the US to visit my husband for long periods of time luckily as i work for a school board. But it has me very confused as you need biometric but someone was saying you need a american address. Do i need to submit the form before my travel plans then when im in the states do biometrics?? And do i need it for just 1 singular trip lasting 30+ days or is it after I’ve reached 30+ days in the states within the year? Help :(