In order to customize the dashboard touch anywhere on the screen, from there click the pencil or gear to bring up the settings menu.
You can hold the corner squares in blue to adjust the size or shape of the gauge.
Tap the gauge to adjust the components of the gauge.
Adjust the parameters if you'd like to view a different live data item on that gauge.
You can change the title of the gauge, the min and max values to adjust the scaling of the gauge, units, color scheme, or even adjust the warning in order to get advance notice of something going wrong.
Customizing the Look
In order to customize the layout of your dasboard, navigate to the dashboard page and touch anywhere once, it should bring up the grey bar as shown below. For some ideas of what you can make it look like check out