Depending on your size preference you can add them just as you would any Android widget; longpress a free area on the home screen, from the “Add to Home screen” menu select ‘Widgets’, select ‘HD Widgets’, then choose your size. Upon first launch the app walks you through an intuitive tutorial of how to customize the widgets.
Customizing HD Widgets consist of a set of sliders either left/right for clock, background or sidebar. For example when adding 4×2 larger header & weather you can change the header position, meaning the clock can be center, left, right, weather only (no clock), 3 or 5 day forecasts (again no clock)… see samples.
Another example is with the full screen widget which only allows modifying the background and sidebar between 5 day forecast or utilities toggles (Airplane mode, Wi-Fi, Bluetooth, screen orientation lock, and auto-brightness.) The developers promise more toggle options are on the way.
One thing I do like about HD Widgets over existing leading app with the same capabilities, Beautiful Widgets, is that you can edit existing widgets easier. To do so, simply tap the weather to invoke the full weather display, “Menu” button and tap ‘Active Widgets’ to edit.
I have gripes with HD Widgets though, unlike Beautiful Widgets, you do not get animations. Inspired from HTC Sense weather widgets; on rainy days the screen is drippy wet and windshield wipers swipes by to clean them off, clouds float by on drab days or snow falls, etc. this feature I miss. :( You do not get the wealth of third party themes for styling clock, weather, and background themes like
Beautiful Widgets or Awesome Widgets Bundle.
When you do launch the weather you have detailed information including degrees in Fahrenheit or Celsius, forecast graphic, 5-day forecast, written weather description, sunrise/sunset, wind speed, direct, etc. plus an option to refresh the weather. More settings such as update frequency and weather service provider can be edited here as well.
Lastly, home screen weather widgets are not only beautiful but convenient for they have shortcuts. Such as tapping the clock portion launches Alarm app or tapping date portion launches Calendar app.