It is a very easy to use tool and I use it every month to do a FULL SCAN of my systems. Note that if you do nothing with the tool, it will run a QUICK SCAN automatically and you will never know this unless it finds problems.
I just ran a Full Scan today. Note that the version of the product is indicated at the top of the first screen you will see. In this case, it is February 2016.
Since the tool is installed every month along with the other Windows updates, it is already on your machines.
Simply click START then RUN then key in MRT and then OK to get it going. If you don't see Run, click on Start and then search for Run.