How to install the double-sided rotating signboard?

1. Fix the backboard installed on the wall with expansion screws.

2. When the wall of a building is not allowed to be fixed with screws, first stick the double-sided adhesive tape on the back plate, then stick it on the wall after the wall and back plate are clean, and then fix the central square and four sides with glass glue. When fixing, the level of the backboard must be ensured.