Select one or more site sections, categories, and sub-categories a user has viewed items from. Click once in the list to select and click the 'Add' button to add to the selected categories list on the right.
To remove added categories, select the category in the list on the right and click the 'Remove' button.
Add a timeframe constraint. This could be the same as the experience timeframe, a start and end date, in the last number of specified days, or more than a specified number of days ago.