The Glass is electronicly released from the area by the license plate light in the coupe. One reason not to keep your jumper cables in the tailgate. Because if the Bartery is dead, the glass will not open. Without the glass open, you can't open the tailgate manualy.
So in the end, If you have an arm full of stuff and you want to put them into the cargo area of the Coupe, you need to electronicly release the Glass either from the key fob or by touching the little button. You then need to pull back on two levers. If you only have one hand its a back and fourth motion at least 3 times. This mod will cut it down to release right, release left, gate goes down