If you want a clean job, take it to a professional.
If it doesn't matter to you, start by removing the center air vent, if you don't have interior/upholstery tools you can pry it out with a flat tip screwdriver.
Remove the two screws at the bottom of the dashboard's shade. Remove the whole dash assembly by pulling it towards you, this includes the driver's air vent.
For some, these are easier said than done.