It's quite a basic circuit board. Start with an Arduino tutorial to get a feeling of hooking up electronics (Adafruit is probably a good start), once you've got it working look up a KiCad tutorial to turn it into an actual PCB.

The trickiest parts here are dealing with the MCU (look for example schematics to copy, they're probably already in the datasheet), sourcing parts (Mouser/Farnell/Arrow are expensive but have good search tools - LCSC is dirt cheap but has terrible search), and soldering the PCB (stick with through-hole parts, if at all possible). You can get a bare PCB of this size made at JLCPCB or a dozen other places for less than $5 - not including shipping.