autoplay timout is the time one slide stays = 1000 ms or 1 sec
speed is the duration of the transition effect = 2000 ms or 2 sec

https://www.norbertinecanonesses.org/help-us-build
the slide changes every 3 seconds per the numbers above ^^

The default if we don't change it looks to be : autoplay timeout of 8000 (8 seconds) at a speed of 800 (0.8 sec)