Step 1 - Find your server cabinet or switch panel or your main router box are.
Step 2 - Check all cables are plugged in
Step 3 - Check all power cords are plugged in and lights is on
Step 4 (School) - Check your uplink pppoe adapter's cables and power cord is plugged in and lights is on.
Step 5 - If you still experiencing no internet connection (please ask for permission) reboot your router.