I used the 1.8.5 Arduino IDE to load the sketch. To install the Arduino IDE and Windows drivers, follow these instructions: https://learn.adafruit.com/adafruit-arduino-ide-setup/arduino-1-dot-6-x… -- the tutorial calls out for version 1.6, but the "latest IDE download" button gets you 1.8.7. There is currently a bug in Arduino 1.8.7 which requires you to select a Port before upload but we don't use Ports for Pro Trinket uploads. If you don't have a Serial Port available to select, please use Arduino 1.8.6
The sketch is actually based on the double-staff project, not the poi project, because I'm using the 5v Pro Trinket instead of the normal Trinket, so there's way more memory capacity. I'm including the script that works on these; I don't know your level of Arduino skill, but I've only learned by trial and error. There's lots of stuff in the double-staff sketch that's extra because that project uses a remote control.
You can comment it out if you want, but that's more trial and error.