Update Publications

Log in to admin area of website
From the admin homepage, click on Pages and then All Pages on the left. Then hover over the page you want to edit (which will have the name of the publication) and click Edit
Click on the file on the page and then click on the Replace button

You will then be given a pop up to select the file from your computer

Once you have done this, the new file should be displayed on the page
Click the Update button in the top right of the screen