If another ability of a source you control triggers when attackers are declared, such as that of Hamlet Captain, you may have it resolve before or after that of Hanweir Garrison
Each split card has two card faces on it, and each card face represents an individual spell you can cast
The stack is one of the zones where cards and other objects can be placed during a game, like the hand, deck, graveyard or battlefield
Sine Mono-Green decks generally are creature and combat-focused, this makes Craterhoof Behemoth especially terrifying, as the X values will likely be very high, allowing you to swing out with giant creatures, all that gain trample to likely take anyone, if not the entire group of players out in one combat phase
Boros Convoke is all about small creatures, and with a full board of those Arabella can dish out a huge life swing every turn
Nissa is a huge reason for that