How can I add url using QR code when the unit is in another province or state

The QR code just gives you the local address of the box (like you see on the top right for entering into a PC), which is a mini web server (running on the box) which allows you to use your PC/Phone/tablet or other device to add a server to the box.  You need to effectively be on the same network to do that however, since most home internet services and routers use NAT to allow internet access to the whole home via a single public IP. 

One way to act as if you are on the same network, is to have a VPN configured on the remote site, which you can connect to and then you would effectively be on the same network when you connect.  I have that setup at my home, so if I want to change anything when I am not home, I can ask the wife to go to the server settings screen, and then I can do the rest remote after VPNing into my home.  But not a smple task for the non-techie.

The other option is to use Port forwarding.  You can use DDNS to have an easy way to know the remote IP of the router of the user you want to connect to (or the user can give you that IP manually - easily achieved by user visiting something like whatismyip .dot. com ), and then his router needs to be configured to redirect whatever port you want from the outside world, to the internal IP of the Buzz box and the port (8090) that is expected.

The way I do it with some of my friends, is that they start "QucikAssist" on their windows laptop, and I remote connect to their laptop and use their browser on their PC to connect and make the mods I want.

Another option is to use the integrated "Teamviewer Quicksupport" app that is already on the buzztv box.  You can download the teamviewer client for your PC.  Your user can launch the Teamviewer agent on their box, and once they connect, they can give you the Teamviewer ID, so you can remote control their box.

The QR code is nothing more that the http://192.168.xxx.xxx:8090 url which you need to visit to add a server.