Hi, I'm new here

[novice]

Hi everyone,
here are the technical details of my "problem"!
The machine, as shown in the picture - a 3020T engraving/milling device.

I hope the picture shows!?
So as stated before, I'm able to load mach3 and steer the axes with the keyboard.
Even modifications of speed and ramps (for the stepper motors ...) are possible with the software.
But when it comes to the USB-Controller - some important things seem not to work.
Here the picture of the board:


In the manual it says that you have to connect limit switches to the I1 - I4 inputs (as printed on the board - common to all switches is the "DCM"-called input ). In mach3 you then configure these inputs in such way that you define the input in relation to the axis - like I2 for X, I3 for Y and I4 for Z.
Interesting enough - in mach3 these Input pins now have different names. As far as I found out I1 correlates to a pin 10, I2 correlates to pin 11, and so on. You can also configure in this section (Ports & Pins...) if you are using a NO or NC switch.
Theoretically you can view your Input setting at the Diagnostics-page but nothing reflected there.

So my general question:
Has anybody experience with this kind of "Chinese Controller" and give me some guidance to get this machine up and running properly? For those who possibly can - be sure to be includes in my evening prayer!!
Cheers
novice