Read Exodus 36:29 Using Other Translations
And they were coupled beneath, and coupled together at the head thereof, to one ring: thus he did to both of them in both the corners.
And they were separate beneath but joined at the top, at the first ring. He made two of them this way for the two corners.
These corner frames were matched at the bottom and firmly attached at the top with a single ring, forming a single corner unit. Both of these corner units were made the same way.