You cannot open part1.rar by itself. It is incomplete.
To successfully extract the contents, you must have all parts of the set in the same folder.
If you only have part 1, you cannot proceed. H-RJ01170484.part1.rar
Do not try to extract part2, part3, etc. individually. You only ever interact with the .part1 file. You cannot open part1
You need software capable of handling RAR files. If you only have part 1, you cannot proceed
If You Use a Mac or Linux (with The Unarchiver or similar):
Direct Extraction: Some extraction tools may allow you to directly extract files from a multi-part archive by simply opening the first part (.part1.rar). The software should handle the rest.