If you haven't already, we recommend first learning more about The Build Your Own tab as this is the tab type we will be using.
Start in your Mobile App builder under Apps > Mobile App, and proceed to add the dynamic item of your choice (Event, Media, Live stream, etc). In this case, I'm adding the most recent media item by selecting Add Item > Media > Most Recent Media > Add 1 Item. Once you do that, be sure to save before proceeding!
If adding a dynamic "Most Recent Media" item you can also choose to add a filter:
List: Shows the most recent Media from any selected list based on the date in the Media Item
Media Series: Shows the most recent Media from any selected Media Series based on the date in the Media Item
This item will now update to display your Media Item with the most recent date as defined in the Date field. This will keep your users informed and help reduce the amount of work you need to do, to keep your app up to date with the latest content from your church.