Can anyone suggest how to design custom hardware for stm32 microcontroller. ie. designing bare minimal hardware of microcontroller to get started with it.

Here are some brief guidelines for designing custom hardware for the STM32 microcontroller:

1) Understand the microcontroller’s datasheet and reference manual.
2) Create a schematic diagram with the microcontroller, power supply, decoupling capacitors, clock circuitry, and peripherals.
3) Provide a stable power supply and follow the recommended voltage levels.
4) Use a crystal oscillator or external clock generator for the microcontroller’s clock.
5) Pay attention to the reset circuitry and boot mode selection.
6) Design the PCB layout following recommended guidelines and consider grounding and noise minimization.
7) Include a programming/debugging interface for easy development.
8) Document your design and consider compliance requirements.