Here's a Java version of the API. It's packaged as a .jar file so just add it as a library resource to your project to use it.
You'll need the line:
import net.codersblock.api.CodersBlock;
at the top of the class you're trying to use it in if your IDE doesn't add it for you.
To use it just instantiate a new CodersBlock object and then it can be used as the tutorial specifies.