When you enable this option, Lightroom for mobile (Android) segments the grid photos By Month (default). You can also choose more segmentation options—By Year, By Day, By Hour.
Sort By > Capture Date | Import Date| Modified Date | File Name | Star Rating
Select one of these sorting options to reorder the display of photos based on the selected criteria. Clicking the option again toggles between ascending and descending orders.
You can also sort by File Name and Star Rating when the Grid Segmentation is off.
Sort By > Custom Order
Use this sort option to manually reorder your grid photos.
Tap the edit icon beside the Custom Order option, to show the Reorder panel. Long-press a photo and drag-drop it to the desired location, guided by a blue markup line that is visible as you drag a photo.
Tap the Custom Order option again to toggle between ascending and descending orders.
You can sort by Custom Order when the Grid Segmentation is off.