Noctua Fan A4 20

Just got the fan
Does it blow up or to the heat sink?
The plastic connector is too big for the screw holes , what you used to hold the fan ?

Also jetson_clocks code turns on the fan but do it gives pwm controls to the fan?

The fan should blow up, pulling heat away from the heatsink and drawing air across the fins.

jetson_clocks sets the fan to maximum speed (pwm=255). The reason it does this is because it also locks the clocks to their maximums and disables the DVFS governor, so it is as if the board is running at maximum performance (for the active nvpmodel mode, 5W or 10W)