Following our basic questions, What’s this? We can add these other demonstrative adjectives (this, that, these, those). In the beginning I always use what’s this regardless of where something, or how many, or if it’s a thing or person. Once they get a handle on this question then we change this to the correct word.
Again, I teach the concept by ad nauseam, not necessarily by explanation. I use whatever is around the room. I ask the question and point. Then I answer using the same word I used in the question.
What’s this? While holding a book
It’s a book.
What’s that? Pointing at a book
That’s a book.
What are these? Touching books
These are books.
What are those? Pointing at a bookshelf
Those are books.
Then repeat with just the demonstrative adjective.
Then I ask the question, and the student repeats the question. I answer.
Then I ask the question, then the student answers.
Then the student asks the question, with guidance.
This lesson is more important than just teaching these four words. From this when can practice pronouncing the difficult th.