I assume by providing a link to pySam, you're interested in the API
more so than the command line toolkit.
There is Doxygen-generated API documentation available if you run
$ doxygen /path/to/bamtools/docs/Doxyfile
and then open the resulting docs/html/index.html in your favorite
browser.
There is also a tutorial available here:
https://github.com/pezmaster31/bamtools/wiki/Tutorial_API_BamTools-1.0.pdf
I am aware that it's quite minimal & needs finishing/updating, but it
does provide some basic starting code.
I apologize for the lack of a one-stop, comprehensive tutorial, but
between the Doxygen API docs, the tutorial and the accompanying
toolkit code, developers should be able to be able to get up and
running. The Doxygen docs, especially, are actively maintained and
should reflect the current state of the API you have your hands on at
any time. There are code examples in there, as well, where explanation
may be needed.
Please feel free to contact me if you have any specific questions
about API usage.
- Derek