NO! You are supposed to open the spell, copy all triggers and variables, then paste them onto your map. The custom ability should also paste, and then you will be able to implement it onto a hero. You NEVER EVER import maps, unless you are doing a campaign. I will now endlessly curse you because you are too lazy to look in the FAQ
For the variables, it is easier to check true the field which says that once triggers are copied so are triggers or something like that, into the Preferences menu I think... After that copy the triggers and the variables will copy instantly. Just watch out so global variables are not used by more than one spell... or else they will mess up.