Display Mode
Subfields: you can select the subfields of the repeater. If you choose an HTML Tag, you can select a style.
Dynamic HTML: in this area, you can display your repeater using HTML and Dynamic Shortcodes. More info...
Template: you can choose a template to stylize your repeater. In the template, you can use ACF Fields widget, another ACF Repeater widget if you have a nested repeater, ACF Relationship widget, and more...
If you set the Preview Page in the Template settings, you will be able to see a preview of the row.
Skin
Text: if you want to display all the rows in the same block, for example, for a simple comma-separated list (Red, Blue, Green).
Grid: a grid layout where you can decide how many columns you want to display.
Table: generates an HTML Table, or add advanced interaction controls to your HTML Table using DataTables.
Carousel: for a slideshow visualization, there is a dedicated section to customize it.
List: for an ordered or unordered list of visualization.
Accordion: for an accordion with all options of standard Accordion Widget.
Source
You can use the Source settings to choose ACF Repeater fields from another page.
Nested Repeaters
To display nested ACF Repeaters, you can use the Template Display Mode on the main ACF Repeater Widget. In the Template, you can insert another ACF Repeater Widget where you can select the sub ACF Repeater as the source.
The Template used for the main ACF Repeater could contain another sub ACF Repeater Widget:
This recursion could be infinite if you keep repeating this procedure to display another sub-level.