You can't stick any kind of file just anywhere on the Internet. The best way to share a written work with the Board is to upload or copy the text someplace like Google Drive (this is especially useful for beta-reading), a journal or blog service (e.g. Dreamwidth or Wordpress), your own website (most webhosts these days come with or are based entirely on graphical sitebuilding services, so you don't have to learn HTML if you don't want to), or in this case, maybe even FictionPress.com, which is FanFiction.net's companion site for original fiction. Then you can provide a link to the webpage containing your document.

However, since you're currently seeking a beta for this work, you shouldn't be uploading or linking it anywhere public yet, let alone on the Board. Stick to a private Google Drive document (or equivalent, if there's a similar service you and your beta like better), or else e-mail the file back and forth with your beta, depending on what they want to do. Save the publishing services for when your work done, beta'd, and ready to publish.

~Neshomeh

The basic premise is that the government started Imprisoning some teens in order to stop the next big school shooting, but the teens founded a resistance group and fought the government.

Fast-forwards 3 years later, and the hero of the book is rescued from his prison by the resistance group, now known as the Youth Protection League(that is the title of the series).

the series is supposed to mock treatment of youth and extreme security polices(e.g. those instituted after 9/11) in the US.