Image placement mode (retired in 1.3.5)
The three-way choice between Prefer Order, balanced and Prefer Aspect Ratio was retired in version 1.3.5. Every project now uses balanced placement for initially placed layouts - aspect ratio first, with the order you selected as the tiebreaker - so there is nothing to set. The tutorial clip below still shows the old Settings panel.
Starts at 52:14 in the full tutorialWatch on YouTube
More in Settings & preferences
See all 14Low resolution and DPI warnings59:03Search settings0:55Keep the existing template when you remove an image52:59Keep the opposite page when removing an image53:37Match aspect ratios or preserve order (retired in 1.3.5)54:08Reset zoom and pan on template change54:42Turn template hover previews off59:35Turn the edge drop overlays off1:00:02Stop blank spreads appearing at the end1:00:25Jump to a spread after dropping photos on it1:00:37Automatic page numbersGuideNon-destructive vs destructive external editing3:46The Return Folder for Lightroom exports5:25