When putting the new arm on there are black alignment lines on the windshield that line up with the blades when 'parked'.

 

Push on the arm a bit up and down. That should pop it free. If not, they make wiper arm pullers. Fairly sure AutoZone loans them out.

 

am i supposed to undo another nut because the arm is stuck there

 

Undo the nut and rock the arm.

You have a 6th gen, btw. This is the 5th gen side of the forum. Doesn't matter in this case since it's the same answer for both.

 

You have a 6th gen, btw. This is the 5th gen side of the forum.

Thread moved to 6th generation forum