Using webdev as PDF repository

I am new to WebDev, and read that this is appropriate place to store PDF to serve perspective clients.

I want to host this repository on the same server where the gateway is.

When I try to create a mountable folder, it lands me to select a folder from my Local Machine, and Network..

What does this means? Does that mean I need to have access to the server, to point to it?
I am not an IT Admin, so I don't have access to the local server of gateway.

The Designer won't be able to see the file resources available to the server.
File related functions at the server scope will only work on files known to the server.
This is one case where you'll want to RDC to the server and launch the designer there instead of on your workstation.
Once you get the file related functionality working, you can return to your workstation for maintenance and all the rest of your regular work.