The Attributes tool allows to edit the attributes of selected element. This tool is disabled (i.e. grayed) when some text or multiple nodes are selected.
The Attributes tool comprises two parts:

The most basic way to specify the value of an attribute is to type it in the lower part, the attributes table. For example, let's suppose you are authoring a DocBook article. Specifying the audience attribute of the root article element consists in
In some cases, for example the class attribute of article, the Value cell contains a drop-down list. In such case, suffice to select an item from this list.
If you want to
remove an attribute, do not specify its value as the empty string.
Instead, right-click on its row in the attributes table. Doing
this pops up a menu allowing to perform various actions on the value of
the attribute being clicked upon. Among these actions, you'll find
Remove.

The upper part, the attribute form, is often used for its specialized attribute editors. For example, let's suppose you have inserted a figure in your document. You may want to give an ID to this figure:
Edit button.Doing this pops down a menu, the very same menu which is
displayed when you right-click on a row of the attributes table. This menu
has an
Edit
item.
This Edit item always displays a specialized dialog box allowing to edit an attribute “more comfortably” than with the attribute form or the attribute table. In the case of the xml:id attribute, the specialized dialog box will show you all the existing IDs. This way you'll be able to type an ID which does not already exist.

The figure you have inserted contains an imagedata element. Its required fileref attribute allows to specify the graphic file which is the source of the image. In order to specify a value for the fileref attribute,
"Browse files" button.Doing this displays a file chooser dialog box (or an URL chooser dialog box, if you have checked FileUse the URL Chooser in XMLmind XML Editor Professional Edition).
Note that by default, the "Browse files" button specifies the value of the edited attribute as an URL which is relative to the location of the document being edited. If you want to specify something else, for example, the absolute filename of a save directory, then you'll have to right-click on this button. Doing this pops down a menu allowing to configure the behavior of this button.
