How to calculate the delta of an option?

Excuse me, could you please explain how one would go about calculating the delta of an option? I've heard it's an important concept in options trading, but I'm not entirely sure how to do it myself. Could you perhaps provide a step-by-step breakdown or an explanation of the formula used? Additionally, how does the delta of an option change over time and in response to market conditions? I'm keen to understand the nuances of this metric and how it can be used to inform my trading decisions. Thank you in advance for your time and expertise.