Hi
@pranavkolte
1. Abort "how to configure the CLK2 pin"


You can config clock2 pin through Chip_SCU_ClockPinMux function.
2. About "set the clock frequency to 1MHz"

You can config clock through blow functions
Chip_Clock_SetDivider();
Chip_Clock_SetBaseClock();
Chip_Clock_EnableBaseClock();
Or you can download and refer to LPC 18XX examples.
LPCOpen Software for LPC18XX | NXP Semiconductors
Hope this will help you.
BR
Hang