The thing with making up conspiracies is you only need a grain of truth and can make up a bunch of shit to make people chase their tails.
The facts seem to be that Hunter Biden was hired in 2014 to sit on a board of Burisma, my best guess (because that really is what anyone is doing) is that in 2014 being the same time that Russia started sending Agents into America to start their war on our democracy and started trolling Hillary Clinton, it makes sense that they would try to manufacture dirt on all of the potential Democratic/Republican candidates that they would not be able to buy off.
Biden's kid getting hired at that time by a Ukrainian company seems to have been exactly that.
https://www.reuters.com/article/us-hunter-biden-ukraine/what-hunter-biden-did-on-the-board-of-ukrainian-energy-company-burisma-idUSKBN1WX1P7
Everything else is Guiliani '7 degrees of Kevin Bacon'ing' a conspiracy together for Trump to use to smear dirt on Biden, because they are scare shitless of running against him, and the Russians know what he is about as does the world who trusts him.