How can I install a benchseat in place of my snot bucketseats?

I need 3 seats atleast and only have 2. This is my work van so I need a way to make more seats but have room. Benchseats are the best bet for me. Can anyone tell me if its hard and how to do it. It will be done so please explain in steps of the how to. I would much appreciate it. I only have one vehicle and its my 89 chevy astro. Shes my baby. New engine goin in next week. Paint goin right after. If youve never had one and peeled some tires you just dont get it. Shes a rock so I need this to be right. If you know how to put a bench in it or can give me more options I havent came up with let me know.