Once they’re fully grown they’re towed into position and allowed to take root.

Close, they pump out all the water, build the structure, then fill it back up again

They wait for an ice age (or a drought, either one will do) before building. When the water comes back, they have Dutch children plug any interior leaks with their fingers.

Someone once said, “What if we just make it super bottom heavy and then put, like, a shit ton of anchors on it? Just a whole bunch of ‘em all over the place.”

And it worked.

I think they drop a big seed from a helicopter and they just grow

“The ocean isn’t going anywhere, it’s too big to move”- The House in the Curulean Sea