You’ll find this post in your _posts directory. Go ahead and edit it and re-build the site to see your changes. You can rebuild the site in many different ways, but the most common way is to run jekyll serve, which launches a web server and auto-regenerates your site when a file is updated.

Directory

Jekyll_Directory_Structure

A basic Jekyll site usually looks something like this:
├── _config.yml
├── _data
│   └── members.yml
├── _drafts
│   ├── begin-with-the-crazy-ideas.md
│   └── on-simplicity-in-technology.md
├── _includes
│   ├── footer.html
│   └── header.html
├── _layouts
│   ├── default.html
│   └── post.html
├── _posts
│   ├── 2007-10-29-why-every-programmer-should-play-nethack.md
│   └── 2009-04-26-barcamp-boston-4-roundup.md
├── _sass
│   ├── _base.scss
│   └── _layout.scss
├── _site
├── .jekyll-metadata
└── index.html # can also be an 'index.md' with valid front matter

Check out the Jekyll docs for more info on how to get the most out of Jekyll. File all bugs/feature requests at Jekyll’s GitHub repo. If you have questions, you can ask them on Jekyll Talk.