Any choices made when the ability resolves won't have been made yet when it's copied by Kirol's ability. Any such choices will be made separately when the copy resolves. If a triggered ability asks you to pay a cost, you pay that cost for the copy separately.

If an ability is linked to a second ability, copies of that ability are also linked to that second ability. If the second ability refers to "the exiled card," it refers to all cards exiled by the ability and the copy. For example, if Tidehollow Sculler's enters-the-battlefield ability is copied and two cards are exiled, they both return when Tidehollow Sculler leaves the battlefield.

If the ability copied by Kirol's ability divides damage or distributes counters among a number of targets, the division and number of targets can't be changed. If you choose new targets, you must choose the same number of targets.

If the ability copied by Kirol's ability is modal (that is, if it says, "Choose one —" or similar), the mode is copied and can't be changed.

Triggered abilities use the word "when," "whenever," or "at." They're often written as "[Trigger condition], [effect]." Some keyword abilities, such as mobilize (from the Tarkir: Dragonstorm release), are triggered abilities and will have "when," "whenever," or "at" in their reminder text. The source of the copy created by Kirol's ability is the same as the source of the original ability.