Not entirely sure if this is the right place but help needed

I just got a used new 3ds xl and I had been curious about modding it so i had been looking on the website to see how it would work until i got to the section where it says to check if it already had custom firmware installed and to mu surprise it did.

Im pretty happy with it already being done for me, but I'm not sure where to go from here. any help is greatly appreciated.