It’s not clear if these are off-site on on-site links you’re talking about. In any case, the link text should be a keyword for the PDF content, for example: Download my report on <link to PDF>10 Top Traffic Strategies</link> for FREE.
Be careful creating non-organic links offsite, especially if your site content doesn’t change much. Google will sniff out and bury offsite links that look unnatural.
There are a few way to do it right. We can carry on the conversation if you like, but I hope that answers your main question.
Site is static and it will have 30 pages, 300 sub-pages with around 2,000 links to download free PDF files from my database.
To be specific its product specifications, (Brand, Year manufactured, product)