Tutorial on adding the USB to Serial to a standalone Atmega328 project?

Working on a small project that will be recreated in KiCad and sent off to a printing factory. Essentially I would like to add an on-board UBS connector for which I need a usb to serial chip like the ch340 and for that I'm wondering if anyone has made a tutorial on the subject of connect one to the Atmega 328.

See the CH340 data sheet (Application 7.2) for the circuit, and replace the MAX232 by your controller.

The baud rate most probably is specified by the USB master, like from Serial Monitor. At least I could not find anything about selecting one of the supported baud rates of the chip.