From the OP:
Basically, during the day, instead of lynching someone, any player may start sequences. If a sequence is passed, whatever the sequence was about happens (kill Hirk sequence would kill Hirk / Spy Maurice would give you Maurice's faction)
There's an in-depth guide to sequence voting on the wiki. I suggest reading that and at least getting a basic understanding of how sequences work. After that, read the voting info in the spoiler above (which contains my slight modifications).
If you want to look over previous games that have used sequence voting, check Host Wars, Amber, and Warcraft III on MM.