Raspi noob looking for guidance on using the board as a HID mouse

This is a hard thing to Google. No Google I do not want a mouse for the Pi I want the Pi to be a mouse. I’m an Arduino guy mostly, and I’m looking to use the Pi in a manner similar to an Arduino (e.g. not going to use an external monitor or what have you) I bought Pimoroni’s ball mouse:
https://shop.pimoroni.com/products/trackball-breakout
in the hopes of adding a mouse to my joystick. However I didn’t realize that it’s not really plug and play with an Arduino. Not REALLY wanting to develop my own library for the Arduino I bought the Raspberry Pi Zero W. Which I realize is massive overkill for this project but, ain’t no kill like massive computational superiority.

So my goal simply is to get the Pimoroni to function as a mouse for a Windows computer. I’ve found tutorials on how to have the Pi be a HID, as well as tutorials on how to make the trackball work. But where I stumble is how do I turn the Pi on? I’ve read dozens of tutorials on how to use the Pi but, they all seem outdated and have the end goal of using the Pi as a computer.

Can anyone help point me in the right direction? I’m really just looking to get "hello world" going on the Pi, in a way that is as functionally similar to an Arduino as I can.