Thank you all. I got it now. The final post of Elektrosatan helped me out, at the end. Yesterday I succeeded the Cascade, I really enjoyed making music with the combination of Rytm and OT. It is amazing and works very well.

One more thing:
It feels like the gain of the recorder is +12 (or more), but it is not set to 0dB. Because of this the recording sounds louder than the original input. Right now I compensate this with the level of the Flex Machine track. I think I will loose quality of the sound like this.

How can I set the input gain of the Flex recorder to 0?
Once I succeeded, but I have been searching for this a lot, and I cannot find it?

Or are there other ways to be sure the recorded loop has the same level (and quality) as the input audio?