Your own server to use the data, or your own LoRaWAN network server?
You must have a LoRaWAN network/application server in the system to actually implement the LoRaWAN protocol and interact with the nodes through the transparent gateway(s).
That is a distinct role from the server which consumes the data.
And it is also a distinct role from the gateway, though there is the demo-in-a-box idea of running a small instance on a gateway’s embedded computer.
Once you have chosen which server you will be using to actually implement LoRaWAN, you then register your nodes with it in the way appropriate to that software, and configure a suitable data feed between that and your server which ultimately consumes the decrypted data.