In order to edit a product attribute, log into your account and navigate to Products > Settings > Attributes.  Find the attribute in the list you wish to edit. If you do not see any attributes you may need to create one first. In the Actions menu select Edit.

Name is the descriptive name of the attribute (the value.) A good way to think about this are things like level of difficulty, color, etc. If you can place these sorts of groupings to your products you can then create useful attributes. So, for level of difficulty you might be able to create things like "Easy", "Medium", and "Hard" or perhaps "Category 1", "Category 2", etc. 

Note: Each attribute should be created individually. So, if you wanted to assign "Easy" and "Blue" to a product you need to create an attribute called "Easy" and another attribute called "Blue".

Once you are done editing your attribute select Save Changes. Clicking Cancel will not save the changes you have made to your attribute.