1 computer, equipped with recording software and a sound card
1 amplifier capable of an aux out/usb out/headphone out
software for editing sound and video, so you can blend the original and the bass recording with a video.
Record your bass while listening to the track, while also recording video.
Place your video in your editing software, line up your bass track, line up your song, export, upload.
I did an instrumental cover of a song in 2013, and learned this stuff the hard way. Well, part of it at least. Cameras are no good for audio recording!