GoGuardian
A smarter way to manage classroom technology.GoGuardian keeps students safe when they're online, helps teachers engage with their students, and provides schools with better control over how their technology is used. With GoGuardian, educators can harness the power of the internet for learning, without harmful content or distractions getting in the way.
Teachers may use this program simply by visiting GoGuardian.com and clicking the Google Login button. Classes need to be created or imported. If you are using Google Classroom, you can import your students and classes as shown here:
Check if a site or video is blocked by using GoGuardian Simulator(video)
Blocking are whitelisting a website(not Youtube)
GoGuardian Help for Administrators