There's a pretty nice tut by Antropus over on his site (https://antropus.com/), but unfortunately the tut is in portuguese, but there are a ton of pictures. He too starts out with a polgonal cube, edits the vertices, extrudes, and what not, and then goes on to change it into a really nice looking sub-D.

...Unless you speak portuguese it might not be such a great tut, but with some basic knowledge of Maya's tools and interface, you should be able to figure it out -- could always try translating the page with Google's tools or so... And if nothing else, the pictures might give you some idea of how to start and where to go...

Good luck...