Inserting links to files in WD Mycloud EX4 in Joomla

I have a WD Mycloud Ex4 NAS and I am trying to use the Joomla app (v 1.03) to host a website from the NAS to have links to download files on the website from the NAS. When I initially tried to do this from the Joomla administrator, the root path for the website only had an images folder and did not allow file upload of even 10 kb(though the size limit indicates 50 MB), from the joomla administrator site. So, I created a 'files' folder in the Joomla root folder path and created a soft link for one of my shares folder (created using the dashboard) to this 'files' folder using SSH. Now, I can get the files from the server when i give the path in my browser url. But I don't know how to give a link in my website that I am creating using Joomla, that points to these files. When I add a new article in Joomla administrator, the option to Insert/Edit Link is disabled. Can anyone help? Also, will the soft links I created be reset when there is a firmware upgrade?