Making a unit use an ability

I was just wonder how I can make a unit use an ability that it has? (without JASS) I noticed that the Unit - Issue Order Targeting A Unit trigger has some ability orders but do those refer to the original abilities in the editor, and if so will just editting those work?

it matter what ability you want cast, if the ability cast instead whit no target (like thunderclap) you have to use Unit - Issue Order whit no Target, the just choose the cast order for the ability, your ability is based on.