Bonnie,
A Lunar return is when the Moon returns to its birth position...about every month. A Solar Return is when the Sun returns to its birth position...every year. The Ascendant returns to its birth position every day. The Saturn return occurs every 28 - 30 years.
The first step in astrology is to understand your birth chart. To learn basic astrological interpretation of your birth chart see:
http://www.geocities.com/wilsontctc
and follow the 6 steps on the site. After you understand your birth chart THEN you can begin to understand some of the other astrology (such as the "Saturn return" you mentioned).
Keeping it simple,
Tim