Hello RBhav.1,
To start developement based on the ST25RU3993-HPEV kit ST offers the schemantic of the board and the FW that is running on the board, both as open source. Please have a look at https://www.st.com/en/nfc/st25ru3993.html were all resources are available.
Further details and resources on the STM32L476 that is used with the HPEV kit can be found at https://www.st.com/en/microcontrollers-microprocessors/stm32l4-series.html. ST also offers a set of software tools that allow to develop application for many use-cases including IOT applications written in C.
It is also possible to use the ST25RU3993 together with other microcontrollers or system on chip solutions as ESP32.
BR