If your stroller takes clip on mud/wheel guards, installation is a snap. This is most easily done by first removing the rear wheels to have access to the frame near the wheel base. To remove the wheels, first lay your buggy gently on its side so the wheel in question is facing upward. At the center of the wheel you will see a silver button (the quick release axle), push this button in whilst lifting up the wheel to remove the wheel.
Next locate the slot on the buggy that the tab on the wheel guards will drop into. This slot is facing upward, and is just above where the axle slips into the stroller. It is right where the plastic of the frame ends and just before where the metal frame begins if you look above the hole the axle slides into.
On the guard itself, you will see 2 sets of tabs. Only one of these will be used to install as the other is not needed, it is there because the guards are meant to be reversible. Select the tab on the guard that if installed would put the guard in the most rear facing position possible, this will ensure you don't get splattered with dirt while pushing the stroller. On each tab there is a forward and a rear 'tooth', the rear tooth is square shaped and will be dropping into the slot described above. The front tooth has a small hole that will click over a small plastic knob facing outward on the stroller, this locks your guard into place.
If you ever need to remove the guard, the tooth with the hole simply needs lifted outward to clear the small knob, doing this while pulling up on the guard will remove the guard itself.