Beginner's Buddhist Course Syllabus By Ancient Pali Canon (Ganthadhura And Vipassanādhura) How to learn dhamma as Māhāvihāra Theravāda Buddhists?

How Māhāvihāra Theravāda Buddhists learn kammaṭhāna and dhamma for over 2600 years?
This is through teacher and student lineages through though the years some changes have occurred. 

Early on the Dhamma was also preserved this way through oral tradition handed down from teacher to pupil.

One of the best preserved lineages is that handed down from Ledi Sayadaw which has teachers like: Saya Gyi U Ba Khin, S. N. Goenka. It is believed that this is the exact teaching transmitted to Burma through Sona and Uttara. This probably would have the best resemblance to that was taught at Māhāvihāra early on.