Pretty self-explanatory, unlock all of the structures by fully upgrading the blueprint table, gaining sufficient progress in each spirit's quest line, and by unlocking abilities at shrines. Ensure at least one of everything has been built.
The only tricky part is that since the guest house gets converted at one point, a replacement guest house needs to be built in order to unlock this achievement.
From Apex Xray:
Bug: Built zipline and salvaged it instantly. The game didn't record that I built it. So I had to build it again at the end of the game for the achievement pop.
I suggest having all the buildings built on the boat at the same time or re-building the ones you might have salvaged once or twice.
So it appears that the achievement description isn't accurate, and that all structures have to exist on the boat at the same time. This would explain why it's necessary to build the second guest house.