I would say that at the level of "foreigner attempting to keep abreast" there isn't too much minutiae and inside baseball you need to be on top of. Here's the basix:
- Democrats win the House
- Trump makes an extremely ill-advised phone call informing the President of Ukraine that Ukraine needs to announce investigations of Hunter Biden in order to get Javelin missiles Congress already released to them
- President of Ukraine agrees to go on CNN
- Whistleblower goes through channels, lawyers up, and informs the House about the phone call
- Ukraine doesn't go on CNN, missiles are released, House calls closed-door hearings, Republicans throw a temper tantrum insisting on public hearings, get exactly what they asked for, everything turns out worse than expected
I mean, you knew about all that. Everything else has been witness after witness confirming that what we knew happened happened and Republicans attempting to make things as boring as possible. There have been highlights - Schiff reading Trump's intimidating tweets into the record so they can try him on witness tampering, Democratic representatives questioning Thumbhead so that they can try Trump on bribery, Schiff entering documents that directly implicate Sean Hannity, Giuliani's Russian thugs directly implicating Devin Nunes - but mile-high view, we knew months ago that the entire Trump administration was illegally pressuring Ukraine for political purposes and we now have congressional testimony that the entire Trump administration was illegally pressuring Ukraine for political purposes.
None of this is controversial. That's basically Adam Schiff's point in the testimony above. None of this shit surprises anyone, all of it had been previously disclosed in closed hearings (so why the fuck did the Republicans demand that it be public?). The Republican argument basically boils down to "Who cares?"
Handy Excuses for Nixon Backers