Topic Sentence, Major Sentence, Supporting Sentence and Concludling Sentence

I want to know more about these sentences which make a paragraph.

  • Topic Sentence: I know that it comes the first sentence in the paragraph, contains the idea the paragraph is about.

  • Major Sentence: Have no idea.

  • Support Sentence: Explains the Major Sentence.

  • Concluding Sentence: The sentences that ends/concludes the paragraph.

Here is an example:-

My grandfather is the most generous person I know. He worked two jobs, one as a barber, the other as a part-time tailor, thirteen hours per day, six days a week for forty year. He sent his three children through college and paid their tuition fees. My father and my two aunts weren’t spoiled, but Grand Pa gave them all they needed to live a comfortable life. Now at the age of seventy, he is still working so he can help his grandchildren, some of whom are beginning college this year. Moreover, my grandfather serves his community. He is a member of charity organization that helps homeless children. A hero, for me, someone who dedicates his life to others, that is my grandfather.

Topic Sentence:
My grandfather is the most generous person I know.

Now, where is the major sentence here?

The teacher only mentioned Support sentences right after the topic sentence:

Support Sentence 1:
He worked two jobs, one as a barber, the other as a part-time tailor, thirteen hours per day, six days a week for forty year. He sent his three children through college and paid their tuition fees.

I don’t know what a “major sentence” would be either. I have learned only the topic sentence / support sentences / concluding sentence structure. In looking this up on the internet, I came across this page which I have never seen before. It has a lot of valuable information, especially the examples of transition phrases:

indiana.edu/~wts/pamphlets/paragraphs.shtml