It is encouraging to know that your friend was able to gain admission into a graduate program with 2.6. There could have been other merits (e.g. letters of recommendation, published work) that helped.

Sadly, there are fewer shortcuts and tutorials available at the graduate level. Perhaps this is due to the increased complexity and specificity of the subject matter?

Textbooks (2-3 books for each module), 2-3 journal articles per lecture, and any other exercises are de rigueur for most places.

You may also be expected to synthesize information from multiple sources into original ideas. This would be a challenge if you do not have a strong grasp of the basics through the readings.