For a children's swing with tower

when I bought the kids swing with tower last year, of course, raised the question: How do I attach the swing?
I came across by chance on the ground anchor, ordered it and tried.
The swing is Bombenfest.
The anchors are easily screwed and screwed with a screw on the object to be anchored.

The nice thing is, of course, that the anchor can be removed without a trace which is not possible with a concrete anchor.

Of course, is to say that it arrives on the nature of the soil, whether these anchor "simple" screw.
I also had the last 10cm fight that I had screwed the anchor to the desired depth.