To ensure compatibility, look for Portraiture v1.0.1 or v2.3 . These versions were the "gold standard" during the CS2 era. Step-by-Step: Installing Portraiture in Photoshop CS2
Keep "Fine" and "Medium" details at high levels, but lower the "Large" detail slider to avoid a "plastic" look.
Navigate to your Photoshop installation directory (usually C:\Program Files (x86)\Adobe\Adobe Photoshop CS2\Plug-Ins ).