Disable Serial Console on Raspbeery Pi 3

I am attempting to add a Protoneer CNC hat to my Raspberry Pi 3 running Ubuntu Mate 16.04. This board uses the serial port vis the GPIO header on the pi.
There is much information online regarding how to disable the default console input/output to the serial port on the pi, but only for other distributions. These methods do not work with Ubuntu Mate.
Has anyone else been successful with this?

This link might help, https://www.abelectronics.co.uk/kb/article/1035/raspberry-pi-3-serial-port-usage