Need Help With Ability Triggers

Need Help With Ability Triggers

ok i've learned that i have a problem with explaining things. so i'll be clear as possabile with this problem of mine.

ok i have a new map like all of those Custom hero wars. but with more of a selection on heros and spells and items that arent sooo broken if you get my drift. now every map has a shop that sells abilities even though they are just items. i got the trigger down to give abilities but i dont know how to lvl it up. plz help

Just check if the unit already has the ability, if he has it, then use this:

Set lvl of *ability* to lvl of *ability*+1 (to get 'lvl of ability+1' first choose 'arithmetic')