Planets are like actors in the chart. Each planet represents an urge looking for expression.
Signs in the chart are the roles the actors play. Think of them as panes in a stained-glass cathedral window. A planet’s energy, its “light,” will come across differently depending on the sign it’s in, or the color “glass” through which it shines for you.
If you want to understand the 12 signs on a deeper level, learn about their elements and modes.
Memorize the mode and element for each sign! This will make it easier to find and interpret the aspects.