This Tutorial Shows a Quick Way to Add a Full Screen Image With Text Overlay in the Center of the Screen
The fastest way to do this is using one of the pre-made blocks that is build with exactly this layout.
The block is set to a height of 100vh (viewport height) and 100% width, which means it will take up the entire width and height of any screen you view it on.
Simply change the background image, edit the text elements or add or remove elements as needed and save.
We can use CSS Flexbox (via the right side config panel) to vertically center the text (or optionally at the top, bottom or stretched vertically).
We can also center the text horizontally, or left, right or stretched as well.
Using the pre-made blocks will let you have this up and running in minutes.
The Video Below Shows How to Make Sure the Image Is Full Width On All Screen Sizes
The video above doesn't go through adjusting the display for all device sizes, so I made another short tutorial showing how to make sure your image is full viewport height (vh) on every device size.