Welcome to Ingo, dizzy. You can mount rimfire rings directly on top of the receiver. The following picture shows Warne brand rings, but other brands will work as well, as long as they are dovetail Rimfire rings. There are other methods as well, but this is the simplest approach. Lots of YouTube videos on how to mount scopes. Very helpful for the first time.
This is a model 581, but it should be the same as yours. If it looks different, it's because I took off the plastic piece in front of the receiver. I tried to rotate the picture, but it keeps coming up like this.