How do I go about building my own arduino pcb based on ATmega808 or ATmega1608?

Is there a tutorial that I can follow to build a custom arduino pcb using the ATmega808 or the ATmega1608 as the MCU? I need to interface a 7 segment LCD, a external resonator(to use as a accurate timer) and few LEDs.

On the software part, I have found nice library MegaCoreX that provides arduino support to these MCUs but the library does not have info on how to create the schematic,etc.,

Thanks

Read user manuals and minimal configuration for those chips.

I have a feeling that problem you are trying to solve can be solved way easier...

If you really want to make an MCU breakout board my recommendation would be to look at ST MCUs.

If it's an IO issue – MCP23017.

Thank You.

I would will take a look at the stm breakout boards.

My requirement is to have a 4 capacitative touch sensing, would I be able to use the STM's touch libraries with arduino if I go the stm32dino way?