In general, my experience of landing in Coutts was good and positive. The officers on both sides were nice, helpful and professional.
We didn't know what to do for the landing. So, we decided first to ask canadian officers what to do for this procedure. Therefore, we parked the car at the parking lot and went inside the building. The officer said, that in order to do the landing I need to be "seeking an entry to Canada". He said we can either walk, or drive with a car to US. Since it is basically the same building, we walked to the US side. Then we walked back to Canada
The officers help and explain what to do, so just explain why you are there, and ask questions if something is not clear
Good luck!