It runs Android Lollipop and that makes it difficult to do.
For starters, it involves rooting the device and that throws any Warranty you might have out of the window. It could also breach the terms of any contract you might be in with a Service Provider.
The worst hurdle is it also involves third party software named APPS2SD and the developer's own advertising warns against using it and qualifies the results veru highly.
I'll cheerfully write it all up for you but are you sure 16GB internal space is really not enough?