There is a step by step on the firmware page, it should be similar on a Mac. Start there and let us know what step you have problems with.
Yes, I am aware of the instructions but they are quite dated and the link for the drivers no longer exists.
I have downloaded Arduino 1.8.9 and Repetier Host for Mac. Both are installed and seem to be working, i then plugged in the CNC machine via usb but the laptop does not recognize it. I dont really know what to do next.
I dont understand where to change the baud rate.
You should not need drivers, they should come with the arduino install. If you are referring to the MAC thing, I have no idea, I was sure that wasn’t a thing anymore but maybe you still have one of the MAC’s affected by that? Sorry I just have not used MAC’s in a very long time and the one I did wasn’t any different than the PC install.
To address your specific issue. You are not able to select the com port in arduino for your board, that step? Different port, different USB cable?
What type of MAC? what software?
I am using a MAC Air Laptop with OS Mojave (most recent update).
I didn’t know there was a step to select the port, where would i do that.
There is a step by step set of instructions on the firmware page. That page is linked on the home page.