While my son and I were playing a disagreement came up. I had 2 dice showing 1 range dmg (1 yellow and 1 red). Firepower says "Resolve one of your red dice showing ranged dmg, increasing its value by 1, or 2 if you are resolving a vehicle die. I increased the value on the red dice by 1 and resolved it then added the yellow ranged dmg to the total because you are able to resolve all like symbols. He says no because the card states "Resolve one of your red dice". Please help.

Per the Rules Reference Guide, Page 9: " • A player cannot use modifiers when resolving a die through
a card effect, unless the card allows them to resolve
multiple dice of the same symbol."

The little rules sheet that comes with the game is very meh. Go to the Destiny Product page ( https://www.fantasyflightgames.com/en/products/star-wars-destiny/) and look under RULES at the bottom for the 7.9 mb file. It is a 24 page rulebook that covers most stuff.

"Resolve a die" means exactly one die.

Resolving multiple dice of the same symbol is allowed as part of the "Resolve Dice" action, but playing Firepower isn't that.

Basically, any number of things can allow you to resolve dice. The Resolve Dice action is one of them. Many cards allow it as well. Each comes with its own restrictions on what can be resolved, and you should do what the card says.