I have a copy of Blitz Basic 2 also, but have not looked at it yet. I imagine it is similar to most "Basic" languages, and in fact, there is a version of Blitz Basic available for Windows, so you should be able to find some info about Blitz commands and structures on the Internet. I bought my teenage Son a programming book called "Game Programming for Teens" or something like that and was surprised to find that the included CDROM inside had the Windows version of Blitz Basic included on it and that the author had learned to code in both C and C++, then chose Blitz Basic to use for his game programming, so I imagine that it is a powerful and easy language to learn and use.
Did you get any documentation with your copy of Blitz Basic 2?
Basic by definition is one of the easiest to learn, good luck!