Relative links?

I am creating a file that will link to other PDF files.  All the files are on a flash drive.  The finished product will be copied to several other flash drives to be distributed to clients.

How do I even link to the files if I want them to open in a browser?

I know I can create the link and choose "Open a File" and Acrobat will walk me through finding the file, but I want it to open in a browser so I should choose "Open a web page" but then I don't know what to use as the URL.  I have been reading about relative links and I think this is what I need.

I saw an example of someone with the same concept.  The files were on a flash drive and when I looked at the link information it was set to open a web page.  The link itself was /somefoldername/thefilename.pdf  that's it.  And when clicked on it opened the pdf in a browser.  Also key is that I can take that flash drive to any computer and it works.  So I know it can be done, I just am missing a small but significant step.