In MYSTU homepage, choose and click one specified course on the left-hand menu, and then click “Course Material” or click the course name in big size, which leads you to the Moodle of your course.
In Moodle, click the assignment set up by teacher:
Click "Upload files" button to upload your homework:
Click "Add" button to upload your files, and click "Save changes", and then click "Send for marking":
By this way, you have finished uploading your homework and just wait for your grade given by your teacher.