I am just trying to replace the front blades. There is a little button to press behind the wiper blade, where it attaches to the arm. I fiddled with it a bit, but I am afraid I am going to break the whole arm if I put too much pressure on it. Is there a trick to this?

 

use a small flat head to help push the tab in. Pull the blade with the other hand.

 

the arm has a hooked end. depress the button and slide the wiper blade down the arm. you may need to rotate the blade so that when you do this the wiper arm will push into the wiper blade edge as you slide it down along the arm.