First, you need to access your dashboard on wordpress.com
To do that you need to login to wordpress.com, click on My sites:
and on the left column menu, you need to scroll all the way down and find the WP Admin shortcut.
Once you click it you will then be forwarded to your dashboard.
From there go to your posts Menu and click on the Categories.
As you see I have already created a few but you can create a new by simply writing the name of the category on the field that I have marked an then click on Add category.
Now that you have created a category I will show you to set up a page to show articles from that category only.
It’s very easy. You need to go to Appearance > Menus and click on Categories (marked with Green):
Then you will be able to see all the existing categories. Check the one you want as a menu item and click on Add to menu. Then SAVE! Don’t forget it cause I often do and I wonder why it doesn’t work.
That’s it. Now there is a new menu item that shows articles from my category Eating.