Hi Lisa. I can give you a bodgy description.
You need to remove the windscreen wipers at the base to allow the plastic cover under them to be removed.
Once the wipers and cover are off, the wiper mechanism and attached motor will be clearly visible.
You may need to remove the mechanism to unscrew and replace the motor or not. I can't remember. Then refit in the reverse order.
It's something I would take a half hour as it's easy but tricky. Get a couple of mates and allow two hours for the first time.
Now the first and biggest trick is how to find the wiper arm bolts. The bottom of each wiper is a hinged bolt cover. Just flip it from the bottom towards the tip of the blade and it will uncover the bolts. Sometimes the little hinge is hard to open from years of grime. A little wd40 may be required.
That's the hardest bit. If you get the wiper arms off, the rest will be easy. Just make sure you refit the wiper arms in the identical position as removed. Maybe photo them before to assist refitting.
Good luck.