If you need it to work in steps, use a timer:
This will count and update from 0 to 100% every 1.0 second over 10s and then stop; and can be restarted with the same Custom Event. Timers can be (un)paused, too, if needed.
Should you need an animated (a silky-smooth update every frame) progress bar, there are many solutions. While widgets cannot have Timelines themselves, you can:
- have an underlying actor push the timeline’s track values into a widget
- use a widget animation with a repeater
- sample timer’s elapsed time
- update variable on Tick and bind property to the progress bar
- make the animation in material instead
- use some other, more esoteric way…
Do tell if you need an example of any of the above.