In order to connect a Netvox sensor to The Things Network. First, you have to connect the device somewhere, then you can send it a downlink message over the air. that will reconfigure its parameters. Fortunately, most gateways can be put into a local operation mode to facilitate over the air programming. The documentation that is distributed with the Netvox R311W wireless Water detector on this topic is very vague. To connect it into your LoraWAN infrastructure. Use the AppKey, AppEui from the box.

For the RAK7258 in built LoRa Network Server.
Create a new application and enter the AppKey and AppEui provided on the box. For the simplicity of configuration turn on Auto Add LoRa Device.
Startup the R311W and all going well the device should auto register to the gateway.

The next step is to create a device in The Things Network console. Once the device is created, edit its settings. Make sure it is set to OTAA. and overwrite the DevEui and AppKey with the parameters found on the devices box. The AppEui will not be able to be modified. and this is why we needed to connect it earlier to our gateway.

Back in the RAK7258 open up the application you created. In the downlink area, this is where we create the packet and queue it to transmit. In the specifications for these particular commands, they require high bandwidth. So you need to be fairly close relatively speaking.
To prepare the AppEui change.

Turn on confirmed
FPort 8
HEX Bytes 03 00 01 02 03 04 05 06 07 00 00 00 00 00 00 00 00 SEND
HEX Bytes 83 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 SEND
This will change the AppEui to 0001020304050607. So substitute this for the AppEui from The Things Network.
To complete the command either wait for the next transmit window, or press a button on the side.
After the device connects and the downlink packets are delivered. Connecting to The Things Network can be completed by power cycling the device by removing the batteries. If there is no Things Network gateway available the device will not activate.

Once you have the device connected to The Things Network. It is possible to downlink messages there to configure other aspects of the device. This process is also device agnostic and should work for all Netvox devices.