It is recommended that you connect your CPU cooler to the CPU_FAN header, instead of the CPU_OPT header. Use the CPU_OPT for secondary CPU cooling fans that may ship with an aftermarket cooler.
The motherboard connects all components together, be it the RAM, CPU, storage ... The remaining fan headers on the motherboard should be CHA_FAN, PUMP, or M.2. These can be used for various ...