All right, let's ease you in with editing a transcript, because that's just about editing. =)
Subed can synchronize with MPV, so you may want to install MPV as well. If you've loaded subed (and maybe subed-vtt, if I've messed up my autoloads and it doesn't load automatically), you should be able to open the file and then use C-c C-v (subed-mpv-find-video) to play the video. You can use M-SPC to toggle pausing and M-j to jump to the nearest subtitle. You can move your point to a word and then use M-. to split the subtitle at the current playback position or at a point proportional to where your point is in the subtitle if the current subtitle isn't the one playing. M-m merges the subtitle with the next one, and M-M merges it with the previous one. You can see that I've shortened the subtitles until about 6:55, changed things like "Control c Control c" to C-c C-c, turned things into sentences, etc.
Feel free to e-mail me partial edits if you want to check in or ask questions - you don't have to wait until you finish the whole file. =) Let's get you warmed up!