Click on Forums at the top of every page. As you scroll down, you will see different icons for each section. The technical section has the Help Button. Calvin's Corner has the book with King's big head on the cover. If the icon is in color, it means there are unread posts in it. If it's black and white, everything has been read.
A simple double click on the icon marks all threads as having been read.

I haven't used tapatalk in so long, I'm not sure if the view is the same.