The terminal window where you type
interactive commands is not part of yorick. Neither is the text
editor you use to compose yorick programs. The two recommended ways
of starting yorick are either through rlwrap (rlwrap yorick) or within
the emacs editor (emacs -f yorick).
Quickly read the first three chapters of the
user manual. The first chapter,
in particular, is a yorick tutorial.
Quickly read the quick reference.
It contains a much more complete look at commonly used yorick
functions and programming constructs than the user manual; become
familiar with it.
Choose one or more of the demonstration programs and work through it.
make crude 3D plots (yorick computes the projections)
Yorick has a help command and a library command.
Learn to use them, and learn to use your text editor to open and read
the yorick interpreted code in the Y_SITE/i
and Y_SITE/i0 directories. Often, the program
you want to write will be similar to something in those directories.
yorick homepage has much more information about yorick, including
user forums where you can get help.