PowerGraph tutorial is here: https://github.com/graphlab-code/graphlab/blob/master/TUTORIALS.md#cluster
for working with HDFS you just need to just to specify the HDFS path.
By the way our newest GraphLab Create works with Yarn (currently on a single node): https://dato.com/products/create/docs/generated/graphlab.deploy.environment.Hadoop.html#graphlab.deploy.environment.Hadoop
Some methods can be parallelized on multiple nodes. For example: https://dato.com/products/create/docs/graphlab.toolkits.modelparametersearch.html