What you have to do is if a Stud finder doesnt find the studs, you have to use a tiny Pilot drill to find yor studs.Once you Find the Studs, you can use a 1 by 4 to use as a hanger at the back of the cabinets if they have the lip on the back. Meaning ,a space to hold the 1" thick hanger
I would mount the hanger and in turn use the hanger to mount the cabinets.Good luck