: Think of this file as a single puzzle piece. By itself, it is unreadable data. You need all preceding and following parts (part1, part2, etc.) and a program like WinRAR or 7-Zip to "stitch" them back together into a functional folder.
: Ensure all parts (part1 through partX) are in the same folder before you try to open the first one.
: You only ever need to right-click and "Extract" Part 1 . The software will automatically find Part 18 and the others to complete the job.