Tab layout, add the corresponding activity to the manifest?

I am trying to make a tab widget to work on my new project. This is the first time I use the Tab Layout. On go开发者_高级运维ogle android developers resource page, i found this piece of tutorial:

i.stack.imgur.com/8WmIg.jpg (stackflow doesnt allow me to post image, sorry for the trouble)

What I dont understand is, what does the 2 lines under the code means? The part that says, add the corresponding Tags to the manifest file. I do understand what to add, but I dont know in which line and how it is written.