Do you have spray adhesive or spray basting? If its is spray basting what type /manufacture ? Some perform differently than others.
There is a good amount of over spray.. so spread sheets or papers around the area. I usually go at least 18 inches past the edge of the item I am quilting with protection. Usually less is better and lightly spray the item. I know when did my first I used way too much as it just did not seem to be sticky .. but it was. Sometimes it does not get tacky right away. I still pin the outter perimeter , as sometimes the edges will lift in the handling and quilting process. I suggest a small sample 12 -18 inches square so you can get a feel for the nature of spray basting , you can judge how much you you really need and it will help get you past the "first time jitters".