Layer Slider Delay Settings

In the slider settings, it says "The time one slide stays on the screen in Milliseconds. Global Setting. You can set per Slide extra local delay time via the data-delay in the slide element (Default: 9000)". I'm not sure how to change the delay per slide...can you help me find that variable in the slide settings? In other words, I would like one slide to be 4000 milliseconds, and another slide to be 8000 milliseconds, etc.