Seeking assistance with setting up a small CNC machine

Hello everyone,

I'm new to CNC machining and need some help setting up my small CNC machine.

The picture of the machine (with accessories) is joined (see "CNC.pdf")
My initial project involves machining holes into an ABS plastic box, as detailed in the attached "Goal.pdf"

I'm looking for recommendations on which open-source/free milling software might be best for beginner.
And I dont know how calibrate the machine, fix the box and go milling at right position ;-)

If anyone could share their expertise it would be greatly appreciated!

Thanks in advance for your help!

Any support are welcome :
- video (english or french)
- writted tutorial with picture (english or french)
- realtime video assistance (GMT+2, french spoken is better / english possible)
...