am really not getting it. When I play a card into my opponent's chain and it is the last card in the chain (he doesnt add anymore), I know that it plays first during the resolution. I played a card that said to deal x damage to target minion and the app would only let me select one of my own minions to take the damage. When you play on somebody elses chain do the effects not damage them. Can i only do damage to my opponent in my own chain?
The key concept there is that cards in the chain are not in play - until they execute. So if you play a minion-affecting card on your opponents chain, and he had no minions in play before starting the chain, he has no minions in play when YOUR chain cards activate. Conversely, if he played cards in his chain that affect minions and you add minions to his chain, they will be in play when his minion-affecting cards are executed.