I understand that to attach a piece of hardboard (with an art

work painted on it) to Hardie board exterior siding I'm supposed

to screw it through to the studs. The wall shown in the photo

has 4x8 Hardie board panels and aluminum flashing. Where should

I start sweeping the magnetic stud finder to locate the studs?

I don't see any nail or screw heads.

And by the way, did the builder do the siding right? I'm wondering

about the apparent non-flatness of the panels exposed by the

shadows.