Hello,
There are no tutorials, I would just direct you to take a look at the bundled example "Sprite Animations (game rips)/Quedex (ball).spd" for a good simple example of how to animate with overlays.
Basically you need to keep the overlays and underlays separate rather than interleaved, and adjust the "Sprite overlay distance" value in the Project window to suit your quantities.
As far as the animator is concerned, you are just animating a single (underlay) sequence, the renderer adds the overlays according to "Sprite overlay distance".
I hope that helps.