There are several types of instruction mentioned in Buddhist literature: there is the general level of instruction which is the meaning contained in the words of the texts of the tradition; this is called the གཞུང། - Zhung. 

On a more personal and direct level there is oral instruction which has been passed down from teacher to student from the time of the Buddha; these are called the གདམས་ངག།- ‘dam-ngag’.  

On the most profound level there is མན་ངག ‘män-ngag’ - upadesha which are oral instructions provided by one's guru, that are the core instructions that come out of his and his guru's personal realization and which convey the teaching concisely and with the full weight and blessings of personal experience. 

• ཟབ་ཁྲིད། - Zab-Thrid

"Profound Instruction". 

This type refers to a type of instruction which reveals the profound aspects of any given subject matter. It is guidance to the profound.

• དོན་ཁྲིད། - Dön-thrid

“Instruction on the meaning”.

This type specifically gets at the don dam or absolute meaning rather than relative or conventional meaning.  It evokes the atmosphere of the Buddhist teaching more than just presenting the conventions of the words.  The conventional meaning is conveyed e.g. in དཔེ་ཁྲིད།, which is just guidance given according to the words of books without actually evoking the nature of reality for the student.

• དམར་ཁྲིད། - Mar-thrid - "Heart's blood -instruction".  

This term refers to the style of instruction that gets right to the core of the matter at hand. According to the general Tibetan explanation, the name dmar "red" refers to the heart's blood of the matter being.  A second explanation is that it is a type of instruction that show the matter as though it were being completely laid bare, like the red blood / meat that appears when the inner cavity of the body is exposed. 

• དཔེ་ཁྲིད། - ‘pé-thrid’ - "Textual instruction".

This type refers to instructions given by a teacher that explain a subject just according to the conventional meanings written in books without the teacher actually evoking the nature of reality for the student. It is used in contrast to དོན་ཁྲིད། - dön-thrid in which the main point is not to teach the conventions of words but to evoke the atmosphere of the meaning for the students.  It is also in contrast to སེམས་ཁྲིད། - sems khrid which is instruction on the mind done using a variety of means, not only words, to get the student to directly experience the  - སེམས་ཀྱི་ངོ་བོ། - sems kyi ngo bo or essence of the mind.

• སྒོམ་ཁྲིད། gom-thrid

"Meditation instruction". 

This is the general term for practical instructions on how to meditate.

• གདམས་ངག།- Dam-ngag

"Oral instruction".  This term refers to oral instruction which has been passed down through the lineage.  It is more than just the teaching of the texts of Buddhism, which is called the gzhung textual tradition of teaching.  Also, it is an instruction given rather than a mere passing on of the unbroken energy of the oral lineage, which is the lung transmission.  Also, it is different from the oral instruction which has come through the experience of the guru himself or of his gurus, which is the upadesha, the man ngag; oral instruction here is more general and less potent than upadesha.

• མན་ངག།

Translation of the Sanskrit "Upadesha".  Amongst oral instructions called gdams ngag in Tibetan,  upadesha are regarded as the most superior type of oral instruction.  They are oral instructions that carry the full weight either of the personal guru's experience or of one of his guru's experience.  These instructions are usually, though not necessarily, very pithy and short.  They are usually also secret in the sense that they are not revealed readily, i.e., they are only given to suitable students at suitable times.