How does a new KDP writer supposed to market a book?

Because you cannot persuade readers to buy any book in which sentences do not make sense. This shouldn't be “does.” If you don't see the problem, that is a big problem.

A) Build a following on social media, a following of people who will buy your books. Good luck with that. There is very little evidence that social media can translate to sales.

How does a new KDP writer supposed to market a book?

When did bestiality first occur to you and how did it happen the first time? Was it a deliberate decision or it just happened and you allowed it?

C) Persuade book reviewers on BookTok or Substack or someplace to recommend your book. If your book is unreadably terrible, this is probably impossible.

A) that are not actually books.

Or

Would you let your son wear leggings to school?

Or

You cannot effectively promote books

If your book is well presented, well written, and basically free of typos, then

Dwarf sperm whale: The 'pint-size whales' that gush gallons of intestinal fluid when surprised - Live Science

D) that are presented with bad covers, bad descriptions, or ludicrously bad interior formatting.

C) that are unreadably terrible in any other way.

D) Pay promotion services like Written Word Media to promote your book. Legitimate services will not accept your book for promotion if the presentation is crappy or the book is badly written.

"Gasping": Scientists Make Breakthrough Toward Full Cure for HIV - futurism.com

Are you planning to proofread your book to avoid sentences such as

E) Take a solid year to learn how to use Amazon or Facebook ads and be prepared to lose quite a bit of money as you figure it out.

B) that are filled to the brim with typos or errors.

Why are flat Earthers made fun of when they seemingly don't exist? I have only met one flat Earther in 18 years.

B) Build a newsletter mailing list of people who will buy your book because they trust you to write books they want to read. This is slow, but ideal.