You can publish a folder by specifying the path to the folder. The RequestPath is the path that the web server will server the files.
$Folder = Publish-UDFolder -Path C:\data\ -RequestPath "/config"
$Dashboard = New-UDDashboard -Title "Published Folders" -Content {}
Start-UDDashboard -Dashboard $Dashboard -Port 9999 -PublishedFolder $Folder
You can download a file by invoking the request path.
C:\> Invoke-WebRequest -Uri http://localhost:9999/config/hi.txt
StatusCode : 200
StatusDescription : OK
Content : Hello
RawContent : HTTP/1.1 200 OK
Accept-Ranges: bytes
Content-Length: 5
Content-Type: text/plain
Date: Sat, 03 Nov 2018 03:15:34 GMT
ETag: "1d473237a178b85"
Last-Modified: Sat, 03 Nov 2018 03:15:31 GMT
Server: ...