"A," "an" and "the"

I’m looking at “a” and “an,” “a,” “an,” ok? With objects, things.
So, for example, “a car,” “a marker,” “a chair,” “a watch.” “A” with
consonants, “a” with consonants, consonant sounds.
And “an” with apple, an apple, an umbrella, an umbrella, an umbrella, an umbrella, an
apple, an apple, an apple, an apple. It’s connected, you see, an apple. An orange, an
elephant. Vowel sounds. Why? It’s difficult? It’s difficult to
say “a apple,” “a apple,” “a umbrella,” “a umbrella,” “a orange,” “a orange,”
“a elephant.” No, it’s easy, easy to say, “an apple,” “an umbrella,” “an
orange,” “an elephant.” “A” versus “the,” the difference,
the difference between “a” and “the.” Well, “have” is “possess.” I have
three markers = I possess three markers. So, in my office I have one door and one window,
no more, one door and one window. What do I say, “open the window?” “Open
the door?” Or, “open a window?” “Open a door?” I say open “the” door or open
“the” window. One possibility, no more, one possibility. So,
“the” door. “The” is similar to “this,” “that,”
“these” and “those,” it’s very specific, very specific, I point at “the” door,
“that” door, “this” door. You have three doors and three windows. I say open
“the” door, open “the” window, or do I say, open “a” door, open “a”
window? It’s very hot, it’s very hot. Open “a” door, open “the” door? Well
you have three doors, you have three windows, so I asked you, open “a” door, “a”
window. It’s not definite, not definite, not specific, one of three.