Without registering ($) it will recognize machine print (typed text) for
an unlimited amout of time (days). It will also recognize handwritng for
14 days before you need to pay money.
The short answer is: You don't.
As with typed character recognition software you need a dictionary of the
letters of the alphbet (upper/lower case). For handwritng one would
start off with an empty dictionary and 'train' it for everthing that is
written.
I have used SipleOCR, but not the handwritng portion.