48V to 12v to 5 v buck converter

Hey! I’m planning to design a pcb for high power Leds, I want to use 12 V fans and a 5v microcontroller (esp32). I would like to make my own buck converter.
So the question is, how do I reduce the voltage from 48 to 12 v and then 5v for the microcontroller using the same 48V 7A power supply?

I was trying to use a 12v adapter and then decrease the voltage to 5v using an LM2596S but it didn’t work (I’m getting 12v on the output). I got the values from Webench power design tool for Texas Instruments.
Here’s the schematic