Use a tool like WinRAR or 7-Zip to open the file.
Copy the cars and fonts folders located inside to assettocorsa\content . FH_X_2022.rar
If you are working with the .rar file, it generally contains the content folder which needs to be extracted into your Assetto Corsa root directory. Use a tool like WinRAR or 7-Zip to open the file