1. Download ext:
   git clone https://github.com/ductridev/Edmodo-Add-On.git
   Or
   Press on Code green button >br /> --> then choose Download ZIP.
   You have to unzip the zip file to install it.
   After you unzip the zip file, enter this url to your browser : edge://extensions/
   At this tab, please choose Load unpacked to load unpacked extension
   then choose where is your unzip file and click Select Folder button
   You're done!
   If you find out any bugs or want more features, don't hesitate to make new issues for me.