How do we remove this? (the trim next to the driver/ passenger window)

Mine has cracked and I have a replacement

 

what do you mean next to the window?

if it's the upper trim,

take off the door panel (screws on the bottom, by the hinge, and the interior latch) the rest are clips that you pop out. The upper trim has 5 screws on the bottom, followed by clips along the top and sides.

 

welcome to the broken window trim club

 

I just fixed mine with some gorilla glue and painted it black. It looks better than having nothing there.

 

That is one of the weakest pieces on the car. Reinforce it before you install it or it may happen to the new one.