Mind consciousness corresponds to theory, and manas corresponds to direct realization.

How can we prove that the mind consciousness operates at the level of learning knowledge and theories, while the manas operates at the level of practical realization? Take cooking as an example of a dharma: first, the mind consciousness must learn the theories and techniques of cooking. But having learned the theory does not mean one can actually cook. With regard to the dharma of cooking, this shows that one has not yet realized it in practice. 

Then how does one realize it in practice? One needs to personally practice cooking. Practicing cooking belongs to actual operation, and actual operation requires the manas to direct and supervise. If the manas does not understand the theory, it cannot supervise the six consciousnesses in cooking. Thus the manas must repeatedly direct the six consciousnesses to practice cooking. When something is done incorrectly, the mind consciousness must then contemplate and analyze what went wrong and how it should be done—this is the mind consciousness directing the manas to practice the operation.

Once the manas has learned the operation, the mind consciousness is no longer needed much for analysis and supervision; the manas can then direct the six consciousnesses to cook with great proficiency, and thereafter will handle it with ease and consummate skill. The saying "an easy journey on a familiar road" describes precisely the level of skill mastered by the manas. 

Therefore, it is said that the mind consciousness corresponds to theory, while the manas corresponds to actual operation. The theories known by the mind consciousness are of little use; only after the manas has actually realized them do they become of great use. Personal realization refers to the manas personally realizing it, not knowledge and theories that the mind consciousness has learned from elsewhere.