I got a lot of helpful information from Miss Mustard Seed's slipcover tutorial on her blog. http://missmustardseed.blogspot.com/ The idea with pin fitting is to cut your pieces to generally fit the chair/ottoman section, then pin the the sections together inside-out to the form of the furniture.
Side section. An additional skirt section will be added later.
I left the last corner open, then turned the slipover right side out, to figure out the best way to overlap the cording. I pinned that corner and sewed it into place. Here is how it came out. I am going to live with it a couple days and see if I want to try to make any little adjustments. The corners are not exactly the same, but a little adjustment can fix that I think. Next comes the comes a pleated skirt, attached to the bottom with another round of piping inserted. I do best with projects like this if I do a little bit at a time. If I tried to do it all in a day or a weekend, I would get frustrated and it would come out poorly.