How do I install a junction box with NM-clamps?
Method 1


Place the box where you want it and screw it lightly to the stud. 
Run the clamp screws in until they bite into the wood.
Remove the box. 
At the marks left by the clamp screws, drill 1/4 inch relief holes about 1 inch into the stud to make room for the ends of the screws
Reinstall the box.


Method 2


Remove the existing clamps
Knock out the inner discs on the sides (not the ones near the original clamps) by 
pushing one side with screw driver, then wiggling back and forth until it breaks off
Install bolt on cable clamps like these (screw section goes on the outside)