Besides the fact that you need to be familiar with Python, you should be able to get started with MRV quickly by working though the usage guide: Usage.
If you prefer to watch the introduction first, feel invited to the MRV Introduction on Youtube.
MRV uses Sphinx as main documentation system, but Epydoc fills the gap by providing more readable auto-generated documentation.
The sphinx docs provide additional hand-written articles whereas the epydoc documentation pages are created from the source code exclusively.
Besides sphinx’s ability to mix auto-generated pages with hand-written ones, it has a search feature that proves extremely useful: Search Page.
Most modules contain their own documentation. Module and Class doc strings are written in restructuredText to achieve nice formatting.
For your convenience, at the top of each sphinx python module documentation page, a link to the respective epydoc documentation page is provided.
In theory, you will never have to look into MRV’s code yourself, and even if code studies are desired, using epydoc’s ‘source code’ links might be good to start with.