IDK. It’s pretty trivial though.
You’ll follow the guides here to set up the machine and mini-Rambo. Then your mini Rambo can control the machine.
Connecting to the pi is just though the USB. There aren’t any drivers. It will show up as /dev/ttyUSB0 or /dev/ttyACM0 or something like that. In the main interface for CNC.js, you’ll be able to pick an available serial port and click connect.
The raspberry pi needs to have CNC.js installed. I use a board from prontoneer that has grbl installed, do I used his preconfigured pi image: https://wiki.protoneer.co.nz/Raspberry_Pi_CNC_-_Quick_Start_Guide
The only terrible with using this image is that it might not have the Marlin update on the CNC.js version.
The realm of setting up a clean pi image and installing the CNC.js software is simple, but very very open ended. I don’t know if there’s a single guide that would run you though step by step. The closest would probably be something about setting up a pi and then a guide from CNC.js for installing that software. If you get into trouble, Google is your friend and there are a few Linux nerds here, like myself.
I, personally, (and if this makes no sense, then just ignore it) would start with a pi at my desk, with a monitor and keyboard. I’d install an image, boot it up, expand the filesystem, and set up sshd, then disconnect it from the monitor and connect to it via ssh to set the rest up. I don’t have a monitor on mine ever, I just connect through the web interface and ssh to do updates. I also installed avahi and gave it a hostname to find on the network easier.