Disklavier

Hello all, so I am having a lot of trouble connecting an Enspire to internet via apple airport express so that I can showcase Disklavier TV wirelessly from airport express to an apple tv. Perhaps I can run through how far I got and I hope someone can help as I felt like I spent way too much time trying to figure this out. I configured my apple airport express to the wifi network and configured it to be part of my wifi. I was not sure if I should “extend” my network or “create new network”. I tried both other ways (just because I was having so much trouble) but either one didn’t work. Creating a new network just didn’t work and websites wouldn’t load on that new network, and “extending” the network was tough because for some reason the only network it would let me extend was the one that is the business’s across the street, not mine. Anyway, I finally got the airport express to connect to my wifi and it was working fine. I then connected it to the disklavier via ethernet cable and turned the disklavier on. After trying this many times, it finally worked and my disklavier was officially connected to the internet as I was able to put in the account information and play disklavier radio. One thing I was very confused about however, was when I wanted to use the Enspire, I still had to connect to the network titled “DKV_____” which was the same one you use when you want to use your iPhone to play the built in songs. Even though I was connected to this network, it still was online. But, if I selected the wifi network that I configured the apple airport express to connect to in the settings of my iPhone, then the Enspire would not even show up on the list of disklaviers in the app and I could not do anything then. This told me I can only use the disklavier when I selected the  “DKV___” titled wifi network. So, I went back to the “DKV___” network and then tried to see if disklavier tv would work. Knowing that all devices needed to be on the same network, I turned the apple tv’s network to “DKV____” and it connected with no problems and also was sure to make the apple tv use the audio from the airport express, just like I’ve done on the E3. I then selected the “diskalvier tv” button on the app from my iPhone and selected a video to watch. Then I asked my iPhone to “mirror” onto the tv in order to play the video, excited that everything would finally work. Of course, it didn’t as the apple tv then just said there was an “error”. I also tried to select the home network that the airport express is configured to on my apple tv, but then there was not way off mirroring from my iPhone. There I got stuck in a loop of hell trying to make everything work together with no success. I know this is a lot but this is everything I did, any help would be appreciated. 
Thanks,
Michael