'Album order' is available as a customisable sorting option. This can be useful, for example, if you wish for images to appear in a particular sequence in a PowerPoint presentation or Contact Sheet generated from an Album.
To reorder images, you need to view the one Album you are interested in on the File Search results page. You can either find the Album on the Albums page, then click through to view its Files…
or search for Files in the Album using the main search menu at the top of the screen.
When you are viewing one Album on the File search page, you will see the Album title at the top.
Then select the 'Reorder Selection' button...
This will put you into "Reorder mode". At the top of the screen, there is a menu of sort order options. So for example, you could order the files by when they were "Created".
If you would like complete control over the order, you can drag them to different positions.
Once you are happy with your order, click the "Done" button in the top right. This will set your order as the "Album Order"