I have enabled the legend in your project to show you how it's working.
The series is an
array of objects, and every object in that array is a separate series. Every position in your legend is a different series.
Take a look here:
https://codesandbox.io/s/hidden-dream-1 ... api/api.js
If you would like to have all of your flags in one series, then they would have to be in one object in that array.
I hope that I made that clear, but in case of any questions, do not hesitate to write here!