The 7 by 7 puzzle is also the largest n by n WCA puzzle. This puzzle was first invented by Panagiotis Verdes and then mass produced by the Greek company Verdes Innovations SA. This puzzle, like the 5 by 5, has a fixed center piece as well as movable ones. The solution is from Ruwix, as is many of the other solutions on my site. This solution will be for big n by n puzzles, but if you want a more in depth tutorial, then youtube is always a great place to look. The solution is next to the image. Good luck!
7 by 7 Solution