Hi,
As you mentioned, you can set loop for each individual element from the layer, but if you would like to loop the entire timeline animation, please use timeline event to do so.
Could you follow the steps below and see if that works for your use case?
1) Create animation in timeline
2) Add an event label at 0 by moving the playhead (the vertical blue line) to the starting point of the animation, and right-click and select "Add label..." or click the blue downward arrow icon from Event layer.
3) Move the playhead to the end of the animation where you would like to repeat the animation from. Right-Click and select "Add event" or click the gray diamond shape icon from the event layer.
4) Double-click the diamond shape, then Events dialog opens.
5) Select Timeline>gotoAndPlay>Page 1>Label (your label added should appear here). Then Save.
6) Preview on a browser
This way, the entire timeline animation will loop infinitely. If you would like to control the number of times for looping, please use gotoAndPlayNtimes, in stead of gotoAndPlay.
Thanks,
Mariko (GWD team)