When editing markup directly, to add a Bullet, start a line with "*". To add a bullet with additional indention, use two stars. The number of stars indicated produces the desired indentation level. I don't think that there is any control over what bullet marks are used.
This page spells it out as if to a 5-year old. This also covers numbered lists:
http://wikimarkup.wikia.com/wiki/Bullets_and_Lists
