The filename indicates it is the second part of a multi-part compressed archive, likely containing a high-definition movie file (1080p).

: Download and install a decompression program such as: WinRAR: The standard tool for .rar formats. 7-Zip : A free, open-source alternative.

WinZip : Another widely used option for various archive formats.

Do you have of the archive downloaded and in the same folder ? How to merge .part files using WinRar