Can someone exlplain how to setup a SAT>IP DVB-C Tuner from an AVM FritzBox?

I've installed a new FritzBox cable today an now tvheadend shows two new SAT>IP DVB-C tuners automatically.

--> But the FritzBox has 4 tuners?

Channelsearch on the fritzbox was already successfull.

Can some describe how to setup tvheadend to get tv also from the fritzbox?

--> DVB-S2 is aleady setup and working.

Here is a good explanation how to setup the tuners. ;-)
https://blag.nullteilerfrei.de/2017/08/07/using-a-fritzbox-6490-as-tuner-for-tvheadend/