Start programming from scratch

Hi All,

I am new to nordic, i am using nrf52840 development kit and using the SDK nRF5_SDK_for_Thread_and_Zigbee_v3.0.0_d310e71.

I would like to start the program from scratch and I want to know how I can configure the GPIO, enable the interrupt, timmer and other peripheral.

I am unable to find a proper programming guide and API regarding peripherals. So if you guys please share the programming guide/software development guide/API documents with me it will really help me to start the programming.

Thanks in advance

Rohit R