To upload proofs, you must be in entity mode. Make sure that the switch on the top bar is set as follows: 
In entity mode, you will see an area under each field and table labeled ‘Drag file here to upload or click to select a file.’.
If you click in this area, a pop-up will open where you can select the proofs. After choosing the proofs, please click on the ‘Open’ button within the pop-up and the proofs will be uploaded.
Depending on the number of documents you upload at once, it may take a short time for the upload process to be completed. All successfully uploaded proofs are displayed directly below the respective field in the ‘Attachments’ area. If you expand the area, you will see all the proofs listed and can either download individual proofs again or delete them using the buttons under the ‘Actions’ column.
