I understand Legendary creatures are commanders, but what about Legendary Enchantment Artifacts, are they put in the deck or in the command zone?
Is it possible to have multiple commanders in an EDH deck? (Implying it's not the same commmander, but they do share the same color(s).)
Deck and no. When you build anEDH deck you specify one legendary creature as the commander of the deck. This one commander is the only card that touches the command zone. Any other card in the deck is played out of the library, whether it's legendary or not, doesn't matter. Hopefully I didn't confuse you more. Also wanted to add, just because a creature is legendary, it doesn't make it a "commander", as the saying goes, "there can only be one".
You could have say, {Derevi, Empyrial Tactician} and {Roon of the Hidden Realm} both in your deck, and use 1 as commander and switch it with the other between games.
So {Bow of Nylea} goes in the deck, not the command zone?
(also, what is the other colored cards in the group of {Bow of Nylea}? Can someone link them?)
{hammer of purphoros}, {whip of erebos}, {spear of heliod}, {bident of thassa}
Hope this is what you were asking.
And yes all other cards go in your deck only the commander in the command zone
Also wanting to note that emblems, {Sorin, lord of Innistrad} for example, and the new Conspiracy's go into the command zone.
On that note only creatures and emblems can be in the commander zone.