Someone (mag, mangi-) sets the pattern of luck for others in doing something (i-) for the first time.
Imo magsibro a mamana tan āro mahap ta.
You set the pattern of luck as the first to harpoon (fish) so we can get much.
Isibro mo a mayyayo a maganay tan mangābak ta.
You set the pattern of luck to run well so that we win.
Someone (mai-) has set the pattern of luck for something.
Maisibro a dya makahap, as dawa maboysit.
He has set the (bad) luck for not getting anything, so it is unlucky.