If the planets in your chart are the cast and the signs are their costumes, the houses are the rooms they walk into. They are the twelve areas of ordinary life — your money, your home, your relationships, your work — where everything abstract about astrology finally touches the ground.
Signs are the how. Houses are the where.
Your Sun in Leo says something about how you express yourself: warmly, visibly, with a little drama. But the house your Sun sits in tells you where that expression wants to happen — on a stage, inside a home, across a partnership, or at work.
A sign tells you the flavour. A house tells you the address.
How to start reading your own
Find your rising sign — that is the cusp of your 1st house. Notice which houses hold your Sun, Moon, and the busiest clusters of planets. You do not need to memorise all twelve at once; start with the house your Sun is in and watch how often that area of life asks for your attention.