When we are writing about finding something in your project, it is not only about opening the files that you are working on, but also about finding relations within your code.
When you are analyzing your code, it is a very common scenario that you need to go to a particular place where a type is declared.
With ReSharper, you can do this by pressing F12 (Go to Declaration) on your type, method, or property use/call. Another way to achieve this is by pressing Ctrl, moving your mouse cursor above a symbol, and clicking on the left mouse button.
As you need to go to declaration, you probably also want to check where your symbol (class, method, and so on) is used. To do this, just move cursor to your symbol and press Shift + F12 (Find usages). If there is only a single instance of the symbol being used, then ReSharper will just move you there. If there are more instances, then ReSharper will display a new Find Results window with all occurrences...