Create a gist with a file called index.html and any other files you need. Or fork the unconf gist we've set up. The default iframe size is 960 x 600, so if your original example was for something bigger, you may need to update your width and height. Also note that there is 5-minute cache on bl.ocks, so changes may not propagate right away.
Replace the https://gist.github.com segment of the url with http://bl.ocks.org. Note that Chrome these days defaults to https://, but that will break your bl.ock and make you sad.
Observe your new awesome code sample. Click on the number in the title to get back to your gist.
Click on your name to check out your sweet bl.ocks homepage. Notice you don’t have a thumbnail.
To make a thumbnail, you’ll first need a 230 x 120 png (see below for some methods to get there).
Then you can clone your gist repo to your machine and add the file as thumbnail.png. Detailed instructions can be found on d3noob.
###Get excited! Make more! See you soon!