"The current price of a company's stock is $20. The company is a takeover target. If the takeover is successful, the company's stock price will increase to $30. If the takeover is unsuccessful, the stock price will drop to $12. Determine the range of values for the probability of a successful takeover that would make it worthwhile to purchase the stock today. Assume your goal is to maximize your expected profit. Hint: Use the Goal Seek command."

From Microsoft Excel 2019 Data Analysis and Business Modeling by Wayne Winston.

I need to understand how to use the goal seek command in excel for this particular question. If at all possible step by step instructions of how to set this up in an excel sheet would be great.