I am looking for schematics for the exhaust on a 2000 Ford Explorer XLS 4wd

Unless you are experienced and a welder what you are contemplating is a big job. The system consist of the exhaust namifolds, converter assembly, pipes, muffler(s), brackets, clamps, upstream catalysis (maybe two) downstream catalysis, a few oxygen sensors (probably), plus all the rest welded together into one unit. First question to determine is can all the pipes be purchased prebent. If not you need access to the bending tool. Since the vehicle is 12 years old I doubt ready made parts are available for a complete system. Did you get an estimate from a muffler shop? You may want to go in that direction.