Hi
Basically:
Sun sign is your conscious creative vitality - the core you
Moon sign is your unconscious emotional reactive side
Your Ascendant is the way in which you project yourself to the outside world.
These are the three most important astrological influences in your personality (arguably in that order) but
Mercury indicates the way in which you think and communicate
Venus indicates the way in which you consciously relate to others
Mars indicates the way in which you assert yourself in the world
Jupiter indicates how you grow and expand yourself through contact with others
Saturn indicates your boundaries, limits, how you protect yourself and what you fear.
Like Jupiter, Saturn operates at a social level.
The sign in which the planets lie indicates how you express these aspects of your personality, the House position shows the area of life in which you most express them.
The Aspects (as in angles) that planets make show the challenges, and opportunities available to you - what comes easy and what you need to work at in order to achieve.
Collectively they give an indication of your personality.
Your ruling planet is usually the planet ruling the Ascendant - that is the sign rising over the Eastern horizon at your time of birth - If like me, you have Leo rising then your ruling planet is the Sun.
If you have a planet withing two or three degrees of the Ascendant, then some Astrologers will take that as the ruling planet. In my case I have Saturn a couple of degrees from the Ascendant and I tend to take Saturn as my ruling planet (which indicates that I must be a masochist because any sensible astrologer would prefer the Sun as his or her ruling planet)
Sorry to be a bit long winded but the point is that all the planets up to and including Saturn have a significant baring on your personality by Sign and House and the three outer planets, Uranus, Neptune and Pluto will exert an influence through the Aspects they make to the others and through their House position - your personality is the blend they all make.
Blessings
Minderwiz