First of all, I clicked on Getting Started and then Read This First. Here is a quote from page 4: "Help and books for Mathcad Prime 2.0 are on the CD-ROM." The problem is that I downloaded Prime so I don't have any books.
The next issue is that some people (and I won't name names) think the interface is intuitive. Well, maybe if you are the developer or someone who uses it all the time. I find it bewildering.