Stud finders will work and can be bought at most lumber and hardware stores as well as places like Wllmart.
You can also try the old knock on the wall, the stud should make a different sound but not sure if you would hear the difference in a wall with rigid insulation. In our MH that has wood studs and fiberglas you hear the difference.
In ours you can push on the luan and it will give a little where it will not where the studs are.
There will/should be studs beside doors and windows. Electrical boxes are normally on one side of the stud. Have a look in cabinets there may be screws holding them in place.
Once you find one stud they should be 16" on centre.