There are various things you need to consider and free tools that you can use to teach online.
The Teaching Online box below provides guidance on setting up and running online training sessions.
This link from YouTube Channel Teachers Teacher's Tech is a tutorial on how to set up Google Classroom.
Check out the links in the YouTube Channels and Playlists box below to find out more about the following free online tools that you may find useful:
Google Jamboard = interactive whiteboard. You will need to login with a Google account.
Padlet = online bulletin board
Pear Deck = an add-on to make Google and PowerPoint slides interactive
NearPod = similar to Pear Deck with additional functionality
Kahoot = for gamifying learning
FlipGrid = for students to post video responses
EdPuzzle = for adding custom quizzes to videos
and more