Just a note on triggers selecting units for all,
use if/then/else, multiple functions, that way you can include more precise conditions after the first applying it to certain units owned by who ever... this also lets you fill in multiple actions allowing you to be able to use other eents that work in coordination to the event.
(things like triggerin unit, picked unit/play, matching condition, matching player etc..)
Very useful when setting up triggers that involve multiple units doing actions like yours...
Hope this helps someone?