Click on "Drop Box(提出箱)" from the left menu of the course website for each subject and move to the "Drop Box(提出箱)" page.
Drag the file to be submitted to the red area, or click on the red area to select the file.
When you are ready to submit your file, click [CONTINUE(続ける)] to complete the submission of your file. If completed successfully, you will see the submitted file in the Drop Box.
Click [Cancel(キャンセル)] to return without submitting.