This is my first attempted edit, so forgive any mistakes in decorum or process. I tried to make improvements on word choice which I think will be much clearer to people who are new to Jekyll and how the post filenames work.
The jekyll engine will autoload all yaml files(ends with .yml or .yaml)
under _data. If there's a file members.yml under the directory, then user
can access contents of the file through site.members.