Turn off the vacuum cleaner and unplug it from the wall.
Unzip the outer vacuum bag holder or remove the canister top. Squeeze the bag below the hole with your hand, forming a seal. Gently pry the bag’s cardboard attachment off the nozzle, flipping it face up to prevent as much dirt and dust from escaping the hole. Roll the bag hole-down and dispose of it in the trash.
Wipe down the inside of a bag with a pre-moistened dustcloth, wiping around and inside the nozzle as well.
Punch through the pre-cut hole of a new bag with your fingers. Press the top left corner (or the one farthest away from you) of the bag attachment cardboard onto the nozzle. Work your way clockwise around the four corners of the cardboard until the entire cardboard is attached. Give the cardboard piece an extra push to secure it onto the nozzle.
Test that the bag is in place by plugging in the vacuum, turning it on and moving it a few feet. Turn it off, unzip the bag and check that it has remained in place, attached to the nozzle.