Folders will let you group emails for easier sorting. More specifically you want to create two folders to improve inbox efficiency, one for reference emails and one for actionable emails, described in more detail in the original blog post. This can be done in four simple steps, shown below:
To Create a Folder:
On the File menu, point to New, and then click Folder.
In the Name box, enter a name for the folder (this is where you can create your two folders, reference and actionable).
In the Folder contains box, click the type of folder you want to create.
In the Select where to place the folder list, click the location for the folder.
The Microsoft Office site helped me put this together for you.
Let me know if you have any questions in the comments.