How to write that you can't be entered by idle people?

You can write a warning sign on the door, for example, please don't disturb during the break, or please knock at the door if you have anything to do, and such a reminder will do. If others go in, it is appropriate that he doesn't like others. At this time, he will write some beautiful cards on the door. No idlers are allowed to enter. This is a girl's room or something.