Click Add Media button in the left column.
In the Media area, drag and drop files or click Select Files.
In the title field, enter the words you want to show on the page linking to the file you just added.
Add a meaningful description that expresses what the file is or the information you wish to communicate.
Select Link To > Media File so it will link to a file
Click Insert into post
Newly linked text display:
Click Publish/Update to publish the change.