Connecting to a Bluesound Vault 2i

I know there are several Bluesound users on the forum, and I am not getting any support from Bluesound.  I just received an new Vault 2i and I want to control it using a Windows 10 Tablet.  I loaded the BluOS app onto the Tablet, and the Tablet has recognized the Vault.  However, the BluOS app will not open, or recognize the Vault.  Vault is flashing green which means "Looking for a Network".  Can I use this product without connecting to the internet?  If so how?  Do I need a Router?  Will a Router operate without internet access?  All I want to be able to do is connect the Vault to my DAC and control the Vault with my Tablet via bluetooth and the BluOS app.  I don't want to stream anything.  I don't to communicate with any other devices.  Any help, guidance, or clarification would be greatly appreciated by this challenged new user.  Thanks.
OP here.  Here is what I have learned over the last two very frustrating  weeks.  You must connect the Vault to a Router via Ethernet.  The Vault and the controlling device containing the BluOS app (Tablet in my case) communicate via Wifi network.  Bluetooth is only utilized if you are streaming from your BluOS app device to the Vault.  You cannot control the Vault via Bluetooth.  Internet is only required for updates to the Vault.  I will be looking for other methods to get updates since I only use my Smartphone as a Hot Spot for internet connection, and I cannot connect my Tablet to my Wifi network and my Hot Spot (Smart Phone) at the same time.  If anyone has ideas, please let me know.  Can I connect PC to Vault via Ethernet, and PC to internet via Hot Spot?

Another challenge has been finding either the "Reindex Library" or "Rebuild Library" in the BluOS app.  They simply are NOT under the Settings - Music Library where they are supposed to be unless they are hidden.  I have the latest App and Vault.  Again, any input would be appreciated.  Thanks!
I will be sending mine back for refund. Apparently what the OP said above is true. Our hotspot disables wireless once Ethernet is used and connection via wireless is impossible with the VAULT since passwords are employed. 
You can get a wifi extender that has an ethernet connection and use that to connect the Bluesound to that, then the hotspot won’t disable the wireless. Hopefully you can connect the extender to the hotspot, it's easy with a router, not familiar with connecting them to a hotspot.