There are five sense-organs, each in its own domain and separate from one another. They are the senses of the eye, ear, nose, tongue and body. These five senses have the mind as its repository. To be mindful is the repository of the mind. Nirvana is the repository of freedom from the mind.
Develop a detached mind towards the material world and extinguish all its desires completely. Gradually, you will have no more worries and you will have arrived at the state of nirvana, a state of tranquility.
A detached mind means to distance yourself from all values based in the external world. This detachment is from sensation, perception, and consciousness. It is freedom from the values and standards of the external world.
source 9, p.213
source 6, pp.56-60