Interested in doing more advanced computations with Spark?
Check out the offical Apache documentation on Spark: https://spark.apache.org/docs/latest/index.html
You can also see advanced documentation for projects like MLlib, Spark Streaming, Spark SQL or GraphX by looking under Programming Guides at the tab at the top.
You can also find free resources for Spark training at the Databricks Resources page:
http://databricks.com/spark-training-resources