Hi Keryn, thanks for getting in touch :)
The best way to put a PDF into the site is to link to it. You can do this in several ways, but the quickest and easiest is to click Add a New... in the Construction Zone, then click File Attachment. Give your file attachment a Name (this will be the button name on the indexbar of your site) and browse for the file. Click Add and you're done :) When users click the button on the indexbar their browser will load the PDF.
You can also upload and link to a file in a Page. Click the Insert File button on the toolbar, then click the box to browse for your file and upload it. Once uploaded it'll appear as a link in your page. You can click the link and edit it to change the text in the link. You can also change the style of the link to remove the download icon next to it, and/or make it look like a button.
You can also take a look at the File Set module if you have a bunch of files to upload around a similar topic. Each file can have a name and description and the overall area can also have an introductory description.
I hope that helps :) Please let me know if you need any more assistance.
Have a great afternoon!
Founder | Spike@School
Level 1, 6 Garden Place, Hamilton 3204 | PO Box 303, Waikato Mail Centre, Hamilton 3240, New Zealand