The primary may or may not be the starting point. The one starting point we know about is Mifsud hitting up Papadop in Mar 2016 after Papadop jumped from Carson's campaign where he had been an advisor since Nov 2015. Papadop lied about his experience to get on both campaigns. At best he is a doofus. At worst an FBI plant. We don't know who Mifsud worked for but before he disappeared from the face of the earth, Mifsud denied he worked for the Russians.
The bottom line is we don't yet know the starting point. We don't know the exact motivations for the early sting activity we do know about, namely Mifsud. Were the Russians trying to sting Trump? We don't know. Was it US State? Possible, but we don't know. There are other redacted "sources" on the Schiff memo that we don't know, but there many we do now know: Halper sent in as a spy plus Mifsud, and probably Downer. Except for Mifsud they were very obviously part of a sting operation.
What were the motives for the early operations (Mar 2016)? Not to promote Jeb, he was done. Perhaps to spike Trump before the R convention. But perhaps tp create materials for an October surprise against Trump and for Hillary. The people involved like Strzolk were obviously working for Hillary. Perhaps the plan was to sting the Trump campaign as an excuse for an eventual FISA warrant (one was supposedly rejected in July 2016). But we don't know the plan as of right now because we don't know Mifsud's motives and may not have all the redacted sources of "Russian collusion".
For anyone looking at the real scandal we are seeing this was the most corrupt action against a political campaign ever. To imagine the FBI was in the heart of it is mindboggling.
It’s my belief that the Russian angle began because the Dems and the FBI/DOJ were scared out of their minds that someone would release her hacked deleted emails.
This is why the timeline doesn’t add up.