To open multi-part archives:
Drag in all or one of the files that make up the multi-part archive.
Click Extract.
Some archive formats such as RAR and 7zip support splitting an archive into parts (sometimes called volumes). For example, the parts of a split RAR file are usually named Archive.part1.rar, Archive.part2.rar, …, or Archive.r00, Archive.r01, … and so on. The parts of a 7zip archive are usually named Archive.7z.001, Archive.7z.002, …
With Archiver you can open these multi-part archives.
Drag in all or one of the files that make up the multi-part archive.
Click Extract.