Log in to the HTML5 client.
Select the Documents tab available in:
The Administration workspace, if documents are managed at the Project level.
The Work Package Work management workspace, if documents are managed at the Work Package level.
Select a Project or a Work Package in the selector.
Click on the New () button.
In the New Document popup, choose your selected file and click on the UPLOAD button.
The new document is added to the spreadsheet.
Modify the attributes if necessary.