All your published campaigns will be listed in the left hand sidebar.
You can select to view active campaign or all campaigns. If you select Active campaigns you will see your campaigns with active or automated ad sets. If you select to show All campaigns you will see all your campaigns regardless of the status of the ad sets.
Once you select the check box next to the campaign name the ad sets in the campaign will be displayed in the Ads sets pane. You can also see if the ad set is paused or activated thanks to the icons next to the name.