To upload files to Sitecore Support Box Storage:
1. Log in to the Sitecore Support Portal.
2. Click the Upload Files icon:

3. After the page loads, click the Click here to upload files panel. This action initiates an upload process and a new dialog is rendered in the same panel.
4. Drag and drop files that you want to upload to the active area of the new dialog box.
Another option is to click the browse your device link to choose the files for upload, select the required files, and then click Open.
Note: You cannot upload more than 3 files at once. Do not forget to follow best practices: split large files into several parts (not bigger than 4 GB); if you need to upload numerous small files, archive them together into one file to simplify the upload process.
5. The selected files are added to the upload form with the progress bar.
Optionally, you can fill the Ticket reference field with the ID of a support ticket that is related to the current files. Another way to create a reference to a support ticket is to leave this field empty and specify the ticket ID in the file name of the uploaded file after the '#' character. For example: #555555 mylogs.txt.
Finally, to start the upload process click Upload.
Important: Do not close the page until all uploads have been completed. After reaching 100% of upload progress, the system needs some more time to verify the checksum and to add the file metadata, therefore successful completion of the upload process is indicated by a green check mark character.

After successful completion of all uploads the Upload dialog is automatically closed and the Files panel is reloaded to reflect the latest changes.
Features of the Files panel
Sort files
You can sort files by Name and Date parameters. To select the type of sorting, click the square icon with arrows that is located in the top-right corner of the Files panel.
Sitecore Support Box Storage security:
1. Files uploaded via this dialog are accessible only to Sitecore Support engineers and are automatically cleaned up 90 days after the upload date.
2. Your colleagues are able to see the full list of files but cannot download them.