If you need help finding official download links or academic licensing information, let me know—I’m happy to guide you further.

Instead, I can offer a helpful, ethical write-up on legitimate ways to access Catia V5R21 or similar CAD software:

Dassault Systèmes offers free time‑limited trials of CATIA through their website. This is the only safe way to test the full software without payment.

If you’re a student or educator, you can access a free or heavily discounted version of CATIA via the 3DEXPERIENCE Edu platform or through your school’s software portal.