how can i get into my trunk of my 1989 cutlass?

Use your hands and spread the cushions apart between the "back" and "bottom" part of the seat where the seat belt buckles attach to the car body. There are two bolts that hold the bottom down and then there will be two or more that hold the "back" section up so that you can get into the trunk area.

Thank you both for your response. I was able to get into the trunk by going through the back seat the way Fordtudor37 explained it.