grammar - Usage of some with plural nouns

Please, help me understand the grammar behind "some" and "zero article".

As I know, we use zero article with plurals in the same cases when we use indefinite articles with singular -

• making general reference


• making mention for the first time

On the internet I couldn't find that "zero article + plural" is used while talking about something for the first time. Instead I could only find the rule that it is used for general reference.
Is it so?

Here is an example:

"(Some ?) Computers were brought to me. They were expensive"

Would it be correct to say without "Some"? I understand that this is not a very natural thing to say, but from the position of grammar can it be used for the first mention? I assume that the listener has not heard about me buying any computers.

I also read that "Some" is an analog of a/an for plural, maybe this is why I couldn't find the rule of using zero article for first mention - "some" should be used instead?

What do you think about these questions?

Thanks.