We had a great workshop with Middle School Teachers about Google Classroom.
There a lot of great online resources for using Google Classroom, and many of the best are done by Alice Keeler.
here is a link to her site and her 2018 tutorials.
https://alicekeeler.com/google-classroom/
However know that Google Classroom is constantly changing, so pick a tutorial that is not any older than 2018 or 2019 or you might get confused. To make it easier for you, I watched a few tutorials to find a few good ones if you would like to watch and learn more.
Here is a great 10 minute tutorial to get you started:
Here is a great video from a teacher showing what her students need to know to join her Google Classroom Class
Here is a comprehensive tutorial that is much too long for setting up your classroom for the first time, but it goes over everything but is 38 minutes long. https://youtu.be/q9NIca6Xskk
Since Locked Mode is a new tool in Google Quizzes and we had some questions - I wanted to let you know that you can only access this from Managed Chromebooks and if someone is using their phone or a desktop, the quiz will not work. Here is a short video that talks about it and the limitations. https://www.youtube.com/watch?v=3uARN8GQJ_Y In an interesting note- when I looked for a video on how to use Locked Mode - the 4th result was how to Hack Locked Mode to Cheat - Honestly, I believe you will have better results with trusting your students and setting appropriate ethical behavior expectations!