Hello Meierpascal007
The mainboard has the following connections:
1x CPU fan
1x CPU_OPT fan header
1x AIO Pump Header
3x case fan header

However, I recommend connecting the fans to a Corsair Commander Pro.
Corsair Commander Pro (External, 6x)
This way you can control the fans optimally with the iCue software.

There are five fan connections on the board as well as an AiO pump connection.

You can also bundle the fans with Y connectors and plug several into one slot.