Smart lists are the mechanism throughout Marketo to define "who" (which people) to include, whether it's a report, a list, or a smart campaign. Here's how to define a smart list for a batch campaign.
1. Choose a smart campaign, then click on Smart List.
2. Type to search for a filter and then drag and drop it to the canvas. Repeat for multiple filters.
A smart campaign with only filters runs in Batch mode. It finds people in the database that qualify based on the filters and runs all of them through the flow at once.
You can make a smart campaign run on one person at a time based on live events by adding triggers, which puts the smart campaign in Trigger mode.
3. Click the drop-down and choose a filter operator for the filter you chose.
Red squiggly lines indicate errors or missing information. If not corrected, the campaign will be invalid and won't run.
4. Enter the filter value.
By default, people who satisfy ALL the smart list rules are qualified. This can be modified to suit your campaign needs. Check out Smart List Rules for Complex Logic to learn more.
To trigger on live events one person at a time, learn how to Define Smart List for Smart Campaign | Trigger.