Not clear from the post if the OPS is asking if he can do the work in one day, or a competent contractor can do the work in one day. Absolutely a competent contractor can do the work in one day, they have a crew, they have done this many times, they know exactly what they are doing, they have all the parts readily available, they have read the directions on the units they are installing before they show up, etc.
Can you do it in one day? My personal experience putting in an exterior French door may be similar. I had to remove a window, cut out the opening, install the rough framing, install a steel header, level the base, install the door, adjust the door, flash the door, insulate, install exterior and interior trim, fabricate and install a copper drip cap, prep for interior painting, and paint. The house was weathertight after the door was flashed.
It took me about 6 hours to demolish the old window and framing, level the floor, install the rough framing, and install the header. The opening was wide open at this point, we simply covered it with plastic sheet the first night. I did all this work solo, with a little help installing the steel header.
Second day we installed the door and base, adjusted it for square and plumb, flashed it, installed foam, and installed interior and exterior trim. This took about 5 hours or so, much of it taken up following Marvin instructions for flashing and sealing very carefully. We painted the interior several weeks later.
This may seem slow to you, but I had never put in a French door before, and I wanted to be meticulous. If the flashing is done poorly, the door is going to leak, and that is a common problem with exterior French doors that I wanted to avoid.