Preface: I might be just an idiot needing to be told how to use the wooden posts.
I am on Forge 1.16.4 and am trying to use wooden post in my build, but I can't get them to rotate to be horizontal like it shows in screenshots. Once again it might be a very simple question, but a solution would be fantastic.

Place them against the side of the block, as opposed to the top of the block.