This knowledgebase article walks through the various email filtering options on both the phishing emails page and campaign wizard setup page.
Each filter field acts as an AND operator. For example, if the Detection Difficulty is set to 'Moderate' and the Service Geolocation is set to 'Global', then only emails that fit both criteria will be displayed.
Multiple Options In A Filtering Field
When adding multiple values to a single filter, each value acts as an OR operator. For example, if the Detection Difficulty filter has both the 'Moderate' and 'Hard' options selected, then emails of either 'Moderate' or 'Hard' difficulty will be displayed.
Emails that are of a 'Moderate' difficulty AND have their Service Geolocation set to either 'Global' OR 'United States' AND have their Payload Type set to 'Credential Compromise' will be displayed.
Emails that are of a 'Easy' difficulty AND have their Service Geolocation set to 'Global' will be displayed: