For this to work you will need a rooted Android device. Rooting your device is usually a fairly simple process but note that it varies from device to device, so I can’t give you a walkthrough here.

Once that’s done, you’ll need three apps:

Linux Deploy
BusyBox
VNC Viewer

First install BusyBox. BusyBox gives your phone access to Linux commands that it wouldn’t otherwise have and is required for a number of root apps to work. Once you’ve installed it though, you don’t need to worry about it again.