remove the small plastic cover at the base of the blade arm by pulling outward on each side, under that you will find a 5-or 6 mm allen bolt holding the arm on.
Remove that bolt and wiggle the arm off.

The larger cover removes the same way.
Sounds like the wiper transmission went night, night.

You have to remove the plastic cowling covers at the base of the windshield at both sides of the wiper assembly to access the bolts that hold down the wiper assy.

It's not a bad job, but is like a puzzle so if you have never done it before, you will have to pay close attention to how it comes apart for reassembly.

One thing to note is with the coverings removed, the windshild will be exposed at the bottom edge and will crack in a heartbeat if bumped by anything blunt.
I always run a couple lengths of duct tape to protect that edge from sharp objects.

Keep searching here, I think there is a link with pictures on how to do this, sorry I did not have a quick link for you.