You can ONLY create a new post in the new template (This is for bloggers at blogger.com (blogspot))

 However, you can only create the word buttons (links) to the most visited sites in the old template.

So, you have to click legacy template in one window while you create a new post in another window in the new template here at blogger.com (blogspot) in order to share links and word buttons easily with your readers like I do.