Here's a step by step that will get you started:
1. go to https://classflow.com/
2. Click "Login" (Teacher or Student option, Login as a teacher) **Note: Students could also log in to interact with your lessons if you're feeling tech savy:)
3. When the login screen opens click on the "g" at the bottom of the page to log in with your google account.
Select your google account or sign in with your google account.
You should now be logged in.
Here's a short tutorial video to show you how to use classflow. Tutorial Video