How to decode data?

Hi,when i can find my payload ?and how i can decode? , i am using OTAA mode to send data to a gateway in a chirpstack server, i want to decode the data that i receive in the server , for example i send “helloword” , but i don’t have idea how to proceed.

You will want to make use of an integration, of which there are many to choose from. Here is a good overview: