Are you having these files, or were you looking for a newer update for the game?
You only need to right-click Part 01 and select "Extract Here" (using WinRAR or 7-Zip); it will automatically pull data from all the other parts to recreate the full file. Forza Horizon 5 v1.538.198.0.part08.rar
You need all parts (01 through whenever they end) in the same folder to extract the game. Are you having these files, or were you
Typically, when you have files ending in .part01.rar , .part02.rar , etc., you need to keep in mind: Are you having these files
It looks like you've shared a filename for a specific (Part 8) of a Forza Horizon 5 game download.
This specific version (v1.538.198.0) is an older build of the game from late 2022.