This section if for the Galaxy S3 which is a phone. If you're talking about the Galaxy Tab 3 Lite then you won't find much help here.
To get the option for USB Debugging, you need to enable Developer Option. To do that press Menu > Settings > Press the tab to the far right > About Device then tab on the Build Number until you see a little message saying developer options have been unlocked (usually after about 5+ taps) then press back. You should see a new option called Developer Options. Go into that and scroll down until you see USB Debugging and check that off.