Astrological houses divide the sky into 12 sections in the same way that the signs of the zodiac divide the backdrop of the stars in to 12 sections. In a birth chart, these 12 houses are different for everyone based on their time of birth and will change approximately 30 degrees every 2 hours.
These 12 houses represent different areas of our life and the signs and planets that are in each will describe the kinds of experiences and attitudes we have regarding that aspect of our life.
1st House (Aries-Mars): The self, the physical body
2nd House (Taurus-Venus): Material possessions, values, the money we earn
3rd House (Gemini-Mercury): Communication, siblings, early education
4th House (Cancer-Moon): The physical home, family, our upbringing, mother
5th House (Leo-Sun): Creativity, entertainment, children, love affairs
6th House (Virgo-Mercury): Unequal relationships, work, health, daily routines
7th House (Libra-Venus): Marriage, partnerships, legal disputes, open enemies
8th House (Scorpio-Pluto): Death, sex, psychology, joint resources and values, transformation
9th House (Sagittarius-Jupiter): Travel, law, higher education, faith, religion
10th House (Capricorn-Saturn): Social standing, career, authority figures, father
11th House (Aquarius-Uranus): Friends, groups, politics, hopes and dreams
12th House (Pisces-Neptune): Seclusion, subconscious mind, sacrifice, escape and spirituality
Jupiter for example, the planet of luck and expansion, in the 3rd house means we may talk a lot or have many siblings. If in the 8th house money comes to us through others, if in the 2nd we earn money ourself easily. If in the 4th we can have a nice big house or many houses, if in the 9th we have many opportunities to travel, if in the 5th house we like to party or we have many children.
Another important thing to remember about the houses is that each correlates and has the same energy and quality with one of the signs of the zodiac and one of the planets. This can explain why someone who has many planets in the 7th house might FEEL like a Libra even though their Sun, Moon, or Ascendant is not in Libra.