The available panels column provides a listing of all the panels that are accessible to the user but which are not currently displayed on the dashboard.

To add an available panel to the dashboard, select the panel with your mouse and then drag it to the tab you would like to place it on. Alternatively you can click on the right arrow on the right side of the panel.

If there is a panel currently on a dashboard tab that you would like to remove from the dashboard, select the panel with your mouse and place the panel on the list of available panels to remove it. Alternatively, you can remove panel by click on left arrow on right side of the active panel.