We all have to learn lessons in these 12 classrooms depending on where your planets land in your own birth chart, either in natal terms i.e. when you were born, or by transit; which is when a planet apparently spends time in the classroom to teach you a specific lesson.
Transits will give an indication of the lessons you are working on in your life (and the natal chart on your life lessons and purpose), at this point in time which are encouraging you to grow and thus to evolve you!
An accurate time of birth is essential to calculate a rising sign as this point changes sign every 2 hours. Once we have calculated this point you can say that this is the 1st house or sector, and place the other 12 houses in a circle in an anti-clockwise direction. You are then able to ascertain which area the planets fall in and the emphasis or life pattern is in place. It is a blueprint and although it may appear that you are fated to have certain experiences, you always have the ability to flow with your destiny and inner divinity or to obstruct or challenge it. Thus you have free will to choose to grow through joy and release struggle. This can be an important turning point!