How to transfer a folder from my PC to my ReadyNAS

Welcome, I'm fairly new here myself and can tell you this is the right place to ask questions about the ReadyNAS.  There are tons of very smart, kind and helpful people here!

I'm curious to understand why you can't mount your NAS to your PC.

My first question: What version of OS are you running on the PC and the RN204?

I'm running OS6.10.10 on both my ReadyNAS boxes and haven't found any way to transfer folders (or files for that matter) using just the NAS web interface.  I can see where you can create a new folder using the web page though. Have you tried creating a new folder on the NAS with the same name then transferring your files into the new folder? 

How did you transfer files from your PC to your ReadyNAS using just the NAS web interface?  Did you use a ReadyNAS addon app?

At the end of the day I suppose you could just copy your folder(s) and files onto a USB stick, plug it into the USB port on the NAS and transfer the data from the USB stick to the NAS.  This link might help if you're running OS6:

https://kb.netgear.com/7015/Copying-files-from-USB-drive-to-ReadyNAS-OS6

Let us know and again, welcome!