After finishing the front end certificate, I wasn’t sure what to do next, since the Data Visualization learning challenges aren’t available yet. I grabbed an O’Reilly book (Data Visualization for the Web) which is a very accessible introduction to D3. I believe you can read it for free online at that link.
Unfortunately it covers D3 v.3- and the current version is D3 v.4. This did force me to consult the D3 documentation to update some of the code. It hasn’t been too much of a problem. For example, d3.scale.linear becomes d3.scaleLinear, etc.
After getting through most of the book, I figured I’d tackle the first D3 project, the bar chart. It wasn’t easy, but once I slowed down and really understood what I was doing, it came together. Other than some slight scale and font differences, I think I nailed it!