This is the "Help" button.  It is located at the top right of almost every screen in admin and will bring up related information about whatever screen you are on.  So, for example, if you are on the "Add Category" screen it will bring up a short page that briefly outlines the function of the different fields/buttons on the screen.  

  This is the "Links" button.  It is also located at the top right of the screen, however, it only appears on "editing" screens (e.g. "Edit Store", "Edit Category", "Edit Product", "Edit Attribute", etc).  When you click on it a new window will pop up with a list of links related to the item you are editing.  For example, if you click on the "Links" button while editing a category you will receive a link that will take you to that category and allow you to view any changes you have made.  You can also copy it and use it as a direct link from a static page you have on your site to whatever page you are working on.

  This is the "Search/Lookup" button.  If it is located in the upper portion of the screen next to the "Search" field it will allow you to search for specific products or categories based on the name or the product/category code.  It allows partial searches.

It sometimes appears in the lower portion of the screen next to a field, such as when you are adding a category.  In this instance it will allow you to "Lookup" a 'parent' category for the one you are creating.

  This is the "Select" button.  When you click the "Lookup" button, mentioned above, a new screen will pop up with a list of all the products or categories that you can choose from.  When you find the product/category that you are looking for click on the "Select" button located on the far right of the screen and it will automatically insert the code for your selection into the applicable field.

  This is the "Edit" button. It is located on the right hand side of the screen when you click on any link that brings you to a list of products or categories from the side bar in admin.  Clicking on this button will bring you to a screen which gives you the ability to edit ALL options for the item/category.   These options will include headers/footers, description, name, code, etc. 

  This is the "Edit Here" button.  It is located next to the "Edit" button.  This will allow you to edit whatever options are currently selected in the "Display" options.  Click here for an image and brief explanation.  It is also the button you will use to edit an attribute that you have created on a product/attribute template.

This is the "Reload" button.  It is located on the bottom right hand corner of your screen.  You can use this to increase the number of items displayed on the page by typing the number of items you would like to see in the text entry box located to its left and then clicking on the "reload" button.

MORE TO COME...