What is included in BI?

Hello.

I'm new to Pentaho and trying to decide what to download and what to learn.

As far as I've read it seems that:
BI Community edition = Report designer + Mondrian (analysis) + Dashboard
Is it right? (then I don't need to download the report designer zip file)
But it seems that pdi is not integrated/included in BI. Is it right?
Then I would need to download both BI and pdi if I want to use an ETL GUI and create reports of the results.

If I want to work with Big Data I also need to download the big data plugin and data access plugin or are they already included in PDI?

Regards