If toggling between the source and its translation doesn't work, try deleting the translation and recreating it & keep a close eye on the paths. As for the Language Switcher block not showing somewhere or for someone, have a look at its Visibility settings (blocks admin page, under Configure) and make sure there are no restrictions.
I've revisited step 7 and added explanations. Let me know if it is still unclear. I'll also add more links in References block (top-right).