I need to create two sections that will respectively contains only some pdf to downloads. I've never used pdf inside a wordpress websites, my question is how I can display them or in any case had a list of them? I was thinking about attaching the files to the relative post/page, this to avoid confusion between the different files that I will display on the two different sections. Can anyone suggest me a smart and fast way to achieve this (files attaching)?
You should definitely use Advanced Custom Fields (ACF) plugin. Go for the PRO version, since you might need it's functionality (it costs less than 20 USD) and will be one of the best WordPress related investments.
The documentation is amazing and easy to understand even for a complete beginner.