New build Pix 2.4.8

I have the following.
Pixhawk 2.4.8 - 3DR PDB board with 4x deans connectors + 1 x male XTC also 2 pin plug (black / red pwr) and 4 pin yellow, white, orange, green (cannot find documentation as to what these plug are used for)

1000kv motors and 4 x DYS 30A ESCs
Configuring the AT9S appeared straightforward, purple light on the R9DS. Seems to make all the right noises when turned on.

Trying to arm / motor test ZILCH! Motors will NOT move at all.

Attempted plugging in one at a time to CH3, ESCs squeak at 1sec intervals and the connected motor pulses but does NOT spin.

Has anyone tried this set of parts and managed to get motors spinning? No idea what I am missing and not enough experience to tell why, or if parts are faulty. Would appreciate any info on this?