When you import a competitor, you need to label all columns. If a column contains a web link or a link to a pdf, you can label them as PDF or Web Link during the competitor import.
Simply follow the following steps:
Click upload competitors in the Competitors tab
Click "Upload Spreadsheet" and select your spreadsheet
For a column containing the web links, select the heading "Web link" and then type in what the button text should be (this might be "Executive Report" or "Presentation")
For a containing a link to a pdf, select the heading "PDF link" and then type in what the button text should be (again, this might be "Executive Report" or "Presentation")
Learn more about the competitor import here.