Use a search engine to look for "otomi-games.com_C89FAIZ4.rar" directly, as the documentation may be in a forum post or blog article.
What the is (e.g., a game tool, a 3D model) I can help locate the documentation for you. otomi-games.com_C89FAIZ4.rar
Return to otomi-games.com and search for the filename C89FAIZ4 or check the download page where you found it. The documentation is usually hosted alongside the file. Use a search engine to look for "otomi-games
you found the file (e.g., a specific project page, forum post) a game tool