First of all make sure you have the correct wiper blade, there are two different length blades on 147’s depending if the car is fitted with a lip spoiler on the roof, you cannot fit the standard blade if you have a lip spoiler as it is too long! First make sure the wiper blade is in the park position. To fit the blade you need to lift off the protective cover at the base of the blade.
Then remove the securing nut.
Give the wiper blade a wiggle and it will come off. Put the new blade on in the park position and then do up the securing nut. clip the cover down, then lift the arm of the rear windscreen and operate the wiper, making sure that park is in the correct place.