Usage Metrics Report - Field Definitions

Hello,

I am modifying the embedded usage metrics report within my workspace. I was wondering a couple things:

1. Is there a resource out there that has field definitions? I have the link that is in the FAQ page, but wondering specifically about the field definitions for everything available when editing the report.

2. Is there a way to broaded the timeframe. Right now I believe it's 30 days, but wondering if there is a way to adjust that.

Thank you!