If you have downloaded "Dying Light 2 [FitGirl Repack].part1.rar", it is likely the first volume of a split-archive compressed game installer.
: Ensure you have downloaded all subsequent parts (e.g., part2.rar, part3.rar, etc.) and placed them in the same folder.
: Repacks often include a "Verify BIN files before installation" tool. It is highly recommended to run this to ensure no files were corrupted during download.
: Right-click on part1.rar and select "Extract Here" using a program like WinRAR or 7-Zip. The extraction tool will automatically pull data from all other linked parts to create a single setup folder.