You can just look that up, start with control over mail in ballots, what happened to the voting machines, that they're now owned by a rightwong libertarian (hence rebranding to "liberty voting machines") the findings on how the machines can be gamed during the calibration steps that happen everyday morning (if you're in a blue state you can calibrate them to count dem votes as Republican). I suspect that's what Trump meant when he said Musks tech rats helped him with the voting machines. Then there's losing ballots ect... There's a bunch of ways you can manipulate voting without exactly manipuating any single persons vote or voting experiences...

...and you can also just load election related agencies with loyalists to bias monitoring.

All of these things have news stories out there. Just google.