1. Select the "Songbooks" style level:

or alternatively Click the "Songbooks" button, as it will automatically select the "Songbooks" style level:

From now on, all changes that you do will be applied to the "Songbooks" style level, which means that they will apply to all songbooks, theirs songs, and song verses (unless you redefined the style at some higher style level, like for a specific song verse).

2. In the top-toolbar, in the "Background" tab, select a background image:

3. In the top toolbar, in the "Text" tab, select the font of your choice:

At this point, you may want to set additional style attributes, like the font color, alignment, margins, etc.

4. Delete all above style attribute:

This will remove all style changes that have been applied to a specific songbook, song and song verse, making sure that all songs will be displayed identically.

5. Save your changes:

Learn more about VideoPsalm cascading styles:

The flexibility of cascading styles Automatic style level switching

How to change the background of a song or a whole songbook - Cascading styles - Part one