Please explain when I can use an Ally and why?
This really is too broad a question. But I will give you some times that you can.
After you have explored your location you can play many allies to explore again. You have them help you and flip another card.
Some allies can be used when you are making a check. They can only be used when you need to make a check that is either of the type the ally is good at or for a card that the ally is good at. Some help in Combat. Some help in Ranged Combat. Some help in casting spells. Some help in picking up boons. And some give you a bonus to a skill you have. If you do not have that skill you get to roll 1d4 + whatever that ally gives you.
Finally, some ally's can do weird things like examine a location deck or bypass a barrier or dive on the damage a friend may be taking or maybe even summon a villain for you to fight.
Unless the card says otherwise an ally can only be used on your active turn and for checks you are making. (Your Checks vs A Check is the language you need to pay attention to.)
Thanks.
I just didn't seem to get it and your explanation helps.
