That is pretty cool. Is this the one you bought? https://www.harborfreight.com/1090-lbs-capacity-40-12-in-x-48-in-utility-trailer-62645.html
It looks similar, but there are no casters and I don't see lights on yours.
This is the HF trailer I bought.
For the time being, I'm only using the front 4X4 half.....I can easily assemble/add the back 4X4 half, to make it a 4X8. I relocated the lights to the rear just under the deck. Pleasantly surprised that it cam with LED lights.
The black trailer (post #4 Northern Tool) I'll be selling is virtually identical to the red 40"X48" in your link.