The report is publicly available here. [1] This is mostly covered on pages ~22-26. Quite a short read since it's redacted like crazy. The 'massive influence' seems to have been a company that setup some fake accounts on Facebook with a total advertising spend of $100k, and one that also had a few thousand spam bots on Twitter that 1.4 million people had "been in contact with" - a phrase which was left undefined.
[1] - https://www.justice.gov/storage/report.pdf