The Responses table has two ways to narrow things down.
Search
Type in the search box to match text anywhere in a response — a name, an email, a phrase in a long answer.
Filter by field
Pick a field and a value to show only responses where that field matches — for example, only submissions where Region is North, or Rating is 1.
Combining with export
Search and filter both carry through to CSV / Excel export, so you can pull a specific slice (e.g. all responses from one campaign) into a spreadsheet in one step.