Conversion from Weihong NK105G2 DSP Controller to GeckoG540 and Mach 3 on 4 axis rout

Have retained the 4 axis motors. the Fuling inverter and 1,5kw spindle. Have purchased GeckoG540, MeanWell power supply and cooling fans. I am no electrician but can follow the installation with one exception. I can only find on the router one limit/proximity switch CENKE BLE17 - 5F NI/E 30vdc 200ma Fin 5mm, mounted on the top of the x gantry 5 inches from one end with the wire appearing to end up in the spindle housing, I have no wiring details of the router and a search of the router am unable to find any limit switches on the X and Y Axis and not sure if the Z is covered.
Reading all the guff there is talk of limit switches and homing switches which I find confusing.but not where or how they fit in.
Can any one explain in simple terms what I need to put in the way of limit switches or homing switches or one or the both. What are the connections terminals to the gecko and power supply needed. The type of limit switch I may need to buy for the axis. What settings will I need in Mach 3 if any.
The rest of the hook up seems to be well documented.
You assistance would be appreciated
Regards David