That has a feeling of more permanence, that milk is always in the fridge. To just say that yes, there is some in there right now, but sometimes there might not be - Duo's example fits better.

Her damit, darauf, darüber, and so on videos were real eye openers for me. Thanks for sharing.

Thanks. It is really helpful video. It says that "Es ist" is used for particular situations like: now there is milk in the fridge but it is not always there.

But "Es gibt" is used when it is always there. "Es gibt einen Park in der Stadt." There is a park in the city.

Correct, it is not acceptable.

Your sentence would mean something like "There is milk there in the refrigerator" or "There, there is milk in the refrigerator" or "There is milk in the refrigerator there".

But the English sentence doesn't use the word "there" to indicate a location -- using da in the German is inappropriate.

It only uses the phrase "there is" to specify the mere existence of something without saying anything about its location; the location is added later by the "in the refrigerator".

In German, simply ist is enough -- either Im Kühlschrank ist Milch or Es ist Milch im Kühlschrank (with a dummy pronoun es in the second case so that the verb can be the second thing in the sentence).

Or you could use es gibt -- im Kühlschrank gibt es Milch or Es gibt Milch im Kühlschrank. (Of those, the last sentence sounds a little odd to me. I'm not quite sure why.)

So "Es ist" can be used as "There is" or "there are" but I will have to specify the location?

Yes.

And it usually refers to a temporary location. You would use it for things such as "There is a lake between the mountains".