From the app admin, click the Integrate Theme on the left sidebar->Select the theme -> Click the "Go to Theme Editor > App Embeds" button -> Enable the app by swiping the button to turn blue -> Click the Save button
Disable App
From the app admin, click the Integrate Theme on the left sidebar->Select the theme -> Click the "Go to Theme Editor > App Embeds" button -> Enable the app by swiping the button to turn gray -> Click the Save button