Adding a custom nRF52810 board

I am currently using a nRF52-DK development board, and would like to use it to program a custom board with a nRF52810. The development board contains a nRF52832, which is similar but has more RAM and flash memory.

How would you go about defining the custom board? In SEGGER they allow you to use a board.h file to define each pin and component on the board, is it similar here? I saw that the JSON file seems to be quite different from that.