The copper fill can be created with the zone mode (6th icon from top), to create it you either left click and drag the cursor (square shape) or use multiple left clicks to make a polygon but you have to close the shape (where it started).
Then you will see a dialog, select the net where this pad will be connected (usually gnd) the layer and how it will be shown, default is dimmed but I prefer normal, after it is created you can edit it using the cursor and double clicking in the border of the shape.
Play with the settings to get the feeling for it.
Alex