Upload pdf file using file manager;
Change to a page with HTML module and access the Cute Editor;
insert an image;
left-click on an image;
select the hyperlink (chain) icon;
select Browse...
navigate the folder pane on the left to the directory that should contain the desired files to link to;
where they are not...
You can have remote access to the portal or I can supply a web sharing session to review together at the server level.
Thanks,
Dan