Do you want to learn how to setup Hadoop clusters and Zookeeper etc. on bare metal and understand all the maintenance of such a system. Or do you want to learn how to use the tool for enabling data science projects?
If it's the former, companies like Databricks are becoming popular because they abstract a lot of that complexity away: https://databricks.com/try-databricks
Because you're coming at it from scratch I'd strongly advise you look at the future trend and start straight with Spark. It is also made by Apache and is the next generation solution. https://spark.apache.org/
To give an idea of the difference, Hadoop uses Map (transform) and Reduce (action) higher order functions to solve distributed data queries and aggregations. Spark can do the same but it has access to so many additional higher order functions as well. This makes the problem solving much more expressive. See the list of http://spark.apache.org/docs/latest/programming-guide.html#t... and http://spark.apache.org/docs/latest/programming-guide.html#a...
The Spark documentation and interpreter are good places to start.
https://github.com/apache/spark/tree/master/examples/src/mai... (Scala) and https://github.com/apache/spark/tree/master/examples/src/mai... (Python)