First, login to your Promomash Manager account at https://www.promomash.com/login
Then, click on the Documents icon on the left hand side (if you don't see this then you may not have access):
Create a Name and Date for the document
Click on the dotted upload box.
Select the document you want to upload. Then click open.
Click the "Upload Document to Library" button
Your document should appear in the library to the right hand side if successful.