There are a number of ways to navigate your Categories & Products.
1. Category Quick Launch
First there is the handy quick launch category menu on the left of your Admin Area.
Simply click to open, you will see your complete category hierarchy.
Jump straight to your chosen category or subcategory and click to visit.
2. Drill down via category links
To perform various actions on Categories & Products you may need to navigate via this method. Things such as editing, copying, moving, activating/deactivating display, changing display order, sharing products on Facebook.
Click "Categories & Products" in the left menu
You will arrive at the main Category & Products screen.
From here you can click through the Categories until you reach relevant Products
Look for the action links on the right for actions that can be applied to either a Category or a Product.