How this card actually work, i mean can this card declare example 3 allies and then all their defenses count together when you defense?

Yes, Stand Together is an event that you can play at beginning of combat phase. After, you can declare more than one defenders against the attacks of the enemies. For example: you have 5 characters, and you are engaged with 2 enemies: you can declare 3 defenders against first enemy, and 2 defenders against second enemy.

And you add all the defense of the team defender: for example..., first attack you defend with 1defense, 2defense and 1 defense: you the total defense against first enemy is 4 points.

PD: however, if you must deal damage, you have to deal it only to 1 character (diferent than archery, that you can chose the damage points between diferent characters)

Thanks a lot and then that card is pretty useful in my deck