Here is a quick video i created to show how to embed a video from Google Drive to Blogger. I recommend uploading all videos to Google Drive, preferably to a 'Blog Documents' folder that you will never delete. That 'Blog Documents' will maintain sharing settings allowing anyone with a link to access even without a Google Account.
A better option would be to upload videos to YouTube. Unfortunately, at this point, we can not upload content to YouTube on our school accounts in Namibia.
Kahlil (Danai) Maramba,