Coaching on the use of "List Category Posts" plugin?

Folks,

Wordpress: 3.0.1
Atahualpa: 3.4.9

I've been able to fumble my way through customizing my website thanks to all of your great posts, but now have a problem I can't seem to sort out.

I've installed the "List Category Posts" plugin - and tried to figure out how to use it. Unfortunately the documentation in English is cryptic and the rest of it is in Spanish.

I'm an HTML novice - anyone willing to do a little coaching to help me set up a page that displays only one category of post? I know the category number and the category name, but don't know how to use the "short code" as given. Does it go in the HTML editor of the page? Does it go into one of the sections in the ATO setup? Does it go into a PHP page? If so, which one?

Thanks,

Gail NK