The myHealth Hub app "widgets" are modules containing certain data types. For example, the Oxygen Saturation widget tracks and displays blood oxygen level data and works in conjunction with the iHealth wireless pulse oximeter device. The oxygen saturation data displays as aggregate data by date.
Tapping "Day", "Week", "Month", or "Year" on the chart view allows you to see data within those time frames.
Tap the circled plus + button at top right to add a new data entry. Tap the "hamburger" icon (three horizontal lines) to the left of the plus + button to change your view option to a List view. Tap the top left arrow to return to Chart view.
Certain Widgets allow you to use an iHealth device to record data. Please see the article on connecting iHealth devices for more information.