Stud finders are not created equal by no means. Most of you would buy the cheapest one we can. However, the cheap ones just don’t really work that well. I bought a better one a while and I have to say what a big difference it made.
Just go slow and when it starts showing a stud mark the wall with a pencil and when the signal starts going away mark the wall again. And then do it again. One you think you found it. Use a thin nail and nail it in and see if you get a stud. Makes things a lot easier if you’re not on a stud. Otherwise, you could end up with a bunch of holes you don’t want.
Are all stud finders equal? NO, they are not. You’ll find a better one will be much easier to use and more accurate than cheaper ones.