What you can set
Width, auto-advance and its interval, whether it pauses on hover, animation speed, pagination dots, navigation arrows — including arrows only on hover and whether they appear on mobile at all — and swipe navigation separately for desktop and mobile. There is an RTL mode for right-to-left languages.
The same layout works for testimonials you have collected yourself. Add them by hand, or take them through the in-widget review form, and they sit alongside reviews pulled from Google and elsewhere in one slider.
Reviewer name, photo, source badge, date, star rating and your own reply can each be shown or hidden, so a testimonial with no platform behind it does not look broken next to one that has.
Where sliders work on a page
Under the hero, or between two content sections as a break. Sliders need horizontal room, so they suit full-width sections rather than sidebars — in a narrow column use a badge or a list instead.
One caution worth stating: a slider shows one review at a time, so a visitor sees three or four before moving on. If the point you are making is *hundreds of people have said this*, the count in the header is doing that work, not the slider.