[XeTeX] Newbie needs help using packages with XeTeX

[Linda Lanz]

Hello,

Don't laugh, but I have some really basic questions to ask. Nothing in
the documentation helps at all. I'm sure this must be very simple, but
how do I use LaTeX standard features and packages with XeTeX?

If I try something like,

\documentclass[11pt]{article}

\usepackage{gb4e}

I get an "! Undefined control sequence." message. I'm using TeXShop
and have no troubles using things like these in LaTeX files. It
doesn't seem to matter what document class or structure commands I
try, nor which packages.

Even the XeTeX-notes.tex file in the documentation won't typeset
without error. What on earth am I doing wrong? The file is saved in
Unicode, I've got XeTeX selected as the typesetting method, and yet it
doesn't work. I'd like to understand why so that I can learn to use
this better.

The ultimate goal is glossing some Armenian texts, so I'd have
Armenian script on the first line, glossing on the second, and free
translation on the third. Even if I can't get glossing to work in
XeTeX (with gb4e, covington, or any other glossing package), it'd be
nice to be able to use it for articles instead of LaTeX so I can
include Armenian examples easier.

Any help appreciated!

Befuddled beginner,
Linda L.