Hiya!
The Mathcad Prime free trial link is here: https://www.mathcad.com/en/try-and-buy/mathcad-express-free-download
When you fill that out, you'll get an email directing you to the installation page, and then you install the program.
When you install the program, you also need to provision the 30-day full-feature license.
The video here should assist in that:
https://www.youtube.com/watch?v=GXlwfOPglk8
I manage the Creo and PTC Mathcad YouTube channels for PTC, as well as all PTC Mathcad marketing in general.
