nds instructions clarifications

[tgravescs]

The instructions start with "Use spark-submit-template with template"... but its not clear on how to actually use that. I think its more for informational purposes at the top and then its actually used later so I think we should clarify that.

there seem to be lots of templates in the instructions and on first reading its not clear which templates do what. I initially thought the templates in the spark-submit-template section did things in like the query templates section so it might be nice to clarify.

In the query generation section, it might be nice to say multiple streams would be used for throughput run and one stream would be used for power run for all queries. Can you specify multiple queries via --template if you want to say run query 1 through 5?