“So the question is - how exactly was he installed”
Voters is the direct answer so the fundamental question is what made so many voters choose Biden/Harris.
They weren’t forced but rather were influenced.
Numerous people I know voted for Biden/Harris because they couldn’t stand Trump.
Some, like my mother, voted Democrat because, as she has stated, she’ll always vote Democrat because they are the party of compassion rather than greed.
Of interest to me now is how will the voting go in the next election.
Joe Biden did not get 81 MILLION legitimate votes in 2020.
You sound like an election fraud denier.