How do you vacuum up ghost in luigi' s mansion?

first shine your flashlight at them. if you do it right then it will freeze, then you have to press and hold the R button to suck them up. But be careful! They will struggle and sometimes break free of the suction (especially the boss ghosts and the homeowner ghosts like the mom and dad ghost). To prevent this, press the analog stick in the opposite direction of the ghost's struggle path.

This is for gamecube so if you have it for something else i cant help you