It's pretty simple:I would love to GM soon, but I would need a crash course in the behind-the-scenes stuff. Things like role randomization, etc.
Work out how many of the basic roles you need for the players you have. 20 players, for example, would be 4 werewolves, and 16 good guys, give or take roles like the bard or my Handsome Jack. This scales almost always, as with 10 players a healthy werewolf number is about 2.
Then, work out how many of each team will be non-powered. Werewolves, this is usually half/most of the team that are left with no powers. Good guys, usually half or the majority have a power.
Then, use a randomiser (just google search it) to work out who gets what power, not forgetting to account for mandatory roles like the priest. Finally, use the same thing to distribute items and special powers like mayor and copycat to players.
*Ta-da!*
And by the way, yes you're a good enough player Shazam