Please be clear what you mean and use the correct terms and names. Otherwise things will turn into a guessing game.
It’s not exactly clear what you mean above so I will switch over to assumption mode:
Presumably you want to register your device in the Console.
With ‘device grid’ you presumably mean the LoRaWAN Device Repository.
With ‘record it’ you probably mean register it.
You can manually register a device in the console using the Manually ‘tab’ which is next to the From The LoRaWAN Device Repository ‘tab’.
For more information see the documentation (in console see Documentation link bottom-right).
The LoRaWAN library to use, as @cslorabox already mentioned is to use a recent version of MCCI LMIC. For more information see: Overview of LoRaWAN Libraries [HowTo]
You can use the ttn-otaa.ino example that is included with the library as starter sketch.
The following may also be useful: LMIC-node
While LMIC-node does not directly support your Adafruit Feather 32u4 board, it does contain good coding examples for how to use the LMIC library.