This guide will cover start times shortly, but the general launch period is Wednesday, December 17
Fusion Summon 1 Fusion Monster from your Extra Deck using monsters on either field, including this card, but you cannot use other monsters you control as material
There's also a reasonable number of "cast from your graveyard" mechanics at this point, including flashback, jump-start, and aftermath, so there are plenty of options available, although there aren't too many Commander staples that use a "cast from your graveyard" mechanic, so your power level might end up fairly low
50 packs to each of the five grand prize winners, and one pack to 5,000 first prize winners
You might use Strionic Resonator to put an extra bounty counter out, and you'll certainly want to load up a Chevill deck with repeatable removal like Assassin's Trophy and Royal Assassin