I just picked up a home built CNC router. The issue is the wife sold it to me so i wasn't able to ask all the questions as the Husband who built it wasn't there. I can't seem to get into contact with him now.
inside the electrical enclosure has a arduino mega 2560 with a cnc shield, power supply and fan. It has a power toggle switch and 3 other buttons. 3 axis with nema 23 stepper motors. it all seems to be wired up correctly (assumption).
i have a few questions. i downloaded the Arduino software and GBRL. can't seem to get it connected. Maybe my windows 7 laptop is not compatible. There is also 2 USB cords coming out of the enclosure, i've been using the one that is directly coming from the Arduino, should i be using the one coming off of the CNC Shield? do i need to use both?

what do you all reccommend to get me started and going? i'm open to any and all software as i haven't used any of this before. Is there wire diagrams i can check to make sure this is wired correctly. Just starting out and i have no idea where to begin.

Please let me know if this is not the correct place to post this, i'm new to this forum.

Thank you all in advance!