Your Dyson vacuum includes a number of removable parts. The most visible of these is the canister, which is the large clear cylinder at the front of the machine. The canister contains the dust and debris collected by the vacuum, and depending on your model of Dyson vacuum, allows access to at least one of the filters included in your vacuum. To clean these filters, or simply to empty the vacuum of dirt, you're going to have to first know how to remove and disassemble the canister.
Unplug the vacuum and locate the button above the canister. The button will likely have an arrow on it, pointing upward. Push the button.
Pull the canister handle away from the machine. Lift the canister free from the base.
Locate the red thumb button at the top of the canister. Push this down in order to empty the canister of its contents. Be sure that there is a bag directly beneath the canister. The dirt and debris exit the canister at its base.
Open the lid of the canister to access to the pre-motor filter. There is a latch at the base of the handle, which needs to be flipped up. If accessing the post-motor filter, you'll find the lid directly beneath the base of where the canister was seated.