The Loop app will automatically build a widget that will be available on your iPhone. The widget is available in the Today view of your iPhone. Swipe right on your iPhone homescreen and your widgets will be available. The Loop widget maybe at the bottom of your widget list. Scroll down to the bottom of the screen and press the
edit button. That opens an "Add Widgets" screen. If you hold and drag the three horizontal lines on the Loop widget row, you can drag it up to the order you'd like it to appear on your widget list.