How to reach category posts from the nav bar?

This is my site: http://www.tattooremoval.eu

I would like some of the headings in the Nav Bar at the top (ie. Methods) to link to posts in categories (ie. Removal Methods). Anyone know how to do this?

To summarise:
I would like it so that when someone clicks on Methods they are directed to a page with list a post from those the category, Removal Methods.

I’m using a category post widget for the index page.

Hope a WordPress guru can help.

Thanks in advance, Rich!