What exactly does it mean that all things were created through...

What exactly does it mean that all things were created through him ?

Well,......the above is VERY clear, nothing was literally or physically created through Jesus, so lets us let the Greeks do the talking regarding the overall meanings of the true context this through word is used regarding Jesus's creation involvement.
Through = DIA in Greek = through, on account of, because of, by reason of, for the sake of = for all these reasons, for the FUTURE one to be, God and God alone created.
After the heavens were made, all we can draw upon from the Hosts of Heaven is, they were pretty much spectators as the Bible does not show any literal involvement of them in creation.
When man was made we see, "let us make man in our image" = HOWEVER, the Gen's passage and Jesus's words are very clear, God and God alone made man and in His OWN image.

Hi Wotsup,
Once again if you go to Biblehub and look up the Greek word for Dia when it is used with the Genitive, it is never, never ever translated as
on account of, because of, by reason of, for the sake of

Dia when it is used with the genitive is almost always translated as "through"
I have no idea why you repeat a mistake again and again after it has been explained and shown to you time and time again.
It is dishonest and not in the spirit of truth.

We all wish to understand scripture but you can't add words to make it say what you want it to.

Wotsup , remember you bought your land through a real estate agent and
had the plans for your house submitted through council and
are having it constructed through a builder.

You can't deny that the real estate, council or builder exists
You also cannot deny that Jesus existed at creation because scripture says all things are through him