Go to Content > Widgets to see all of the widgets available.
Format the widget by adjusting the height in pixels. The width will automatically scale for you. (We recommend a space fo at least 500px.)
Grab the widget by clicking into the text box next to the widget you want and copying that text. The text will automatically highlight when you click into the box. You can also preview what the widget will look like by hitting the "Preview" button.
Below is the list of available LeagueApps widgets: