Trigger + abillity request

I want help to do a trigger that do so when I click on an item it change to an other item, that got a abillity activated (reveal the entire map). When I click on it again, it change back to the item, that I got first, and deactivate the abillity. When I click on the items, I also want the hero to say some to.

I am not so good at triggers so please tell me all details

Thanks in advance, Jack_Sparrow93

Ehhh, this will maybe also be MY headache... But, it's interesting. But say me, when u click item the second time, it has to reveal the map or to change to another item? Or both?