This is my project to control a CNC machine with a laptop without having to be plugged directly to the machine. This way I can keep my laptop away from the machine which is safer for the laptop. I like to use Rasbian Jessie with Pixel image for my PI's operating system. It can be downloaded from raspberrypi.org for free! Once you boot up for the first time go the the starter menu and find Raspberry PI Configuration. Then go to the Interfaces tab to enable VNC, while here enable SSH and Camera if you think you'll use them. Then for the settings to activate reboot you Pi.
Once rebooted you'll see the VNC icon in the top right of the menu. You'll want to the make sure your connected to a network that both your CNC machine and laptop can connect to. They must be on the same network. My CNC is in my garage which picks up my home WiFi network, then as long as my laptop or phone are within range of that same network I can connect and control my machine. Now remember your Pi's IP address, and shut it down to move it to your machine or location. You can now just plug in power to the PI where you want it to be no HDMI cable no screen.
The following photos are screenshots taken from a laptop. Download VNC Viewer for your computer or just about any device you want. Then enter the IP address you remembered from the Pi setup earlier. Once connected it will ask for login info. The (username is "PI") and (password is "raspberry"). You should now see the desktop of the Pi from your device.
My CNC is powered by a Ramps 1.4 board so I use a program called Pronterface to control the machine. You can follow This Instructable as I did to install it on your Raspberry Pi. Once that is setup and connected we have control of the CNC from our device. There are videos below showing it in action, and with a Pi cam streaming video!
This Raspberry PI starter kit has everything needed to make a remote desktop controller for your projects. Even an HDMI cable for setting it up initially. The strong Aluminum case will keep your Pi 3 protected.