1) Does the first player initiate all of his actions and then the next player and so on?

2) Can other players play their own or activate their own actions in response to another player's action?

Thank You!

Within an action window, players always alternate actions (or pass), starting with the first player. You cannot take an action "in response to" (that's what we call a reaction, it has special timing), but you can take an action because your opponent took one.

E.g. : Marshalling phase begins. First player becomes the active player (the only one who can 'marshal' things), and collects gold.
FP takes an action (kneels winterfell steward)
Next player passes
FP takes an action (marshals a Kingsroad)
Next player takes an action (Uses Lordsport Shipright to kneel the kingsroad)
FP passes
Next player passes (all players have passed)
Next player becomes the active player.

1. See istaril's response. Players take turns initiating actions - you do one, then he does one, etc. - instead of one player initiating all the actions they want before the other guy gets a chance to.

2. You can never respond to an action with an action. You need a "reaction" or "interrupt" ability to "respond" to an action. So, the first player initiates an action, all players have the chance to trigger reaction abilities, then the next player can initiate an action (see #1/istaril's response above), etc.

Alright, thx for the advice guys!