I put in carpet from them years ago in my 73 and like Nova_Guy said, they are oversize and require trimming to fit. You just have to take your time. On my car I started by centering it on the tranny tunnel and then put in the console. This somewhat held it in place to where then I could work on the seats to get them in and pull the carpet down where it should be. After the seats were in I then worked on the kick panels and door sill area's.
Since the carpet set is molded and shipped in a small box folded up you need to take it out of the box on a nice warm day to lay it out and relax so to speak. If it is removed right out of the box and installed you may have problems with creases put into it from shipping.
Be glad you don't have a hatchback. I've got an ACC set for my 74 and ordered bulk, unformed carpet for behind the rear seat and the hatch floor. I was also able to order the welting to where once I have the hatchfloor carpet cut to size I can then have the welting sewn onto the edges.
If you have holes in the floor to attach things to like the seats or console put in the bolts or shorter ones to where you can feel the bolt heads with the carpet on top of them and then use an X cut to get the carpet down around the bolt and then slowly trim it open some more in a circular fashion. You can then pull out the bolt, put in what goes there and run the proper bolt back in and not grab any of the carpet material.