If the mind falls asleep, awaken it. Then if it starts wandering, make it quiet. If you reach the state where there is neither sleep nor movement of mind, stay still in that, the natural (real) state.
The state in which the mind is bereft of any support to cling to, ever faultless and pure, and devoid of worldly attachments, is the nature of liberation attained through knowledge. Keep this firmly in mind.
Dispelling all attachments completely, and fixing that mind in the Heart firmly, persist in your practice always in order to strengthen the awareness, which then shines forth with great effulgence and clarity.
Know that whoever meditates on that supreme void, and becomes established in it by virtue of constant practice, will definitely attain the great state which is beyond birth and death.