How can I view the amount of responses for a campaign?

From the Campaigns List page, you can drill down into each campaign record to view campaign members that have responded to a given campaign, and view campaign member details.

In addition, you can view campaign details including campaign name, start and end dates, status, and other standard or custom attributes. The total number responding to a campaign represents the total count of campaign members with a status of Responded. Note that the response is only counted once even when a campaign member has responded multiple times to the same campaign.