In a funnel analysis, users may have completed steps multiple times within the selected date range. Each instance of those completions may have different property values associated with it.
For example, let's look at a standard checkout funnel:
Landing Page -> Cart View -> Complete Purchase over the last 30 days
A user viewed the landing page and their cart multiple times across multiple devices before completing their purchase. If you segment this funnel by the property "Device", you must choose whether the steps are broken out by the "Device" type observed during the user’s first, last, or all completions of that step.
In other words, using the first, last or all dropdown, property breakouts can be filtered based on the desired instance of step completion within the selected time frame.
First, last, all does not apply to user properties, as they already have a first, last functionality built in. For more information, refer to User Properties.