How many opened, started and completed, where they gave up and which campaign, location and device they came from.
How each Analytics number is counted (views, started, completed, conversion and average time), how to read the funnel, day by day, drop-off by field and the day-and-time map, in the form tab and on the account Analytics page.
How to tag links with UTM, what the form records about where each visit came from (campaign, referring site, landing page, device and location) and where to compare how well each campaign converts.