Answer:
The first one would be that its second hand because A firsthand account is written by someone who experienced the event and may include opinions. A secondhand account is written by someone with knowledge of an event or topic but who did not experience it.
The second question you could put something like the purpose of the author was to inform people about why the people made their voyage on the Mayflower and the challenges they faced in the "new land". The author had a third person POV so they wanted to have that POV because they went there when the article took place.
The best I can do for what was the main Idea in the third question is give you an example of a main idea for a different story, sorry.
The main idea is sometimes found in the first sentence of a paragraph. The main idea is sometimes found in the last sentence of a paragraph. The main idea is sometimes not found in any one sentence. You can figure out the main idea by asking yourself, “What is the most important idea in the paragraph?"
So an example would be: The main idea for green eggs and ham would be Don't make up your mind about something without trying it.
And for the fourth question is sorta simple after you come up with the main idea, just find three things that lead you to believe that the main idea is the main idea.
I really hope this helps you in some way.