How is SLG calculated?

Excuse me, could you please clarify how the statistic known as SLG, or slugging percentage, is actually calculated in baseball? I understand it's a measure of a player's batting prowess, but I'm not quite sure how to derive it from a player's stats. Could you break it down for me, step-by-step, and explain each component in a way that's easy to understand? Thank you in advance for your help!