Hello everyone, any help would be much appreciated

basically i have a MKS base, dual extruders and a fan extender, what I dont know is where to wire the power wires to on the board. Here's a low down of ma problem:





the fan extender goes in the XS3 auxs (there are less pins in the schematic)
where do i connect the wires from the fan extender to the mks base?


thanks !