Flora is the name given to Adafruit’s “wearable” microcontroller. What it really means is that it has some large holes that can be used for sewing to clothing and such. Adafruit provides a number of lessons, one of which introduces you to this tech.
https://learn.adafruit.com/getting-started-with-flora
If you are already familiar with Arduino or similar, you might just want to read the pinout diagram.