Please Help ARF CNC 6040 question on assembly and setup Automatic Voltage regulator

Hi folks, finally after my ARF 6040E has been in it's crate since November last year I have cracked open the crate and am slowly putting things together.
it seems like a long time ago I researched all things CNC and I am a little mist on some details I must admit.
I have a few question I need help with.
Machine ordered and received: https://www.ebay.com.au/itm/254079121105

1.When attaching the stepper motors, does the gantry and z,x & y axis need to be in any particular "homed" position?
it has photcell limit switches, and after googling I can't find much info on how they work.

2. It arrived with a huge Automatic AC voltage regulator SOV dtzm 100000 https://www.aliexpress.com/i/33008519751.html , output is stated as 220V on the box.
I don't remember this being include in the parts list when I ordered it so it has thrown me a little, please excuse my ignorance.
it does not have the two plug sockets in the back like the one I linked to but only the 5 input/output holes with grommets, I have translated that left side as input and right side as output with ground in the middle.
So my question about this is firstly do I need to used this? I'm assuming it is worth including in the power path.
Second, am I right in thinking that I run the mains power to the left side input Live, Neutral and Earth in through the grommets and connected inside the box, and the kettle style lead the goes to the control box will have the plug cut off the end and the Live, Neutral and Earth fed in through the right side Live and Neutral grommets with the earth through the middle grommet to connect in with the other earth from the mains?

Many thanks in advance.