If you want to share or contribute, Please for this repo. and upload files to your forked repo. Then create a pull request and ask the admin of the orginal repo to accept pull request.
You can use master branch directy or create another branch if your contributed codes, slides or notes files changes completely.
There are chances that files or codes has been updated in the ogininal repo you have forked. In such case you need to merge(pull) original repo into your forked repo (called Sync your fork with orginal).