If you don’t have it, download and install it from the official website . Right-Click Alissa.7z.001 : Select the 001 file only.
If you have downloaded a file named , you might be confused as to why it won’t open like a normal ZIP file. The reason is simple: it is part of a split archive . Alissa.7z.001
(e.g., .002, .003) in the same folder?