Model Stock Price Movements In A Column

I have a spreadsheet that tries to model a possible stock price movement in a column. So in column A I have all dates starting from today and in Column B a specific stock's possible stock price movemens onver the next 2 years.

So dates start at A3 and stock prices start at B3 and end at A734 and B734.

This gives me ONE possible stock movement and to get the most accurate movement, I will need to model this 20,000 times.

Therefore, I want to create a loop macro that repeat this motion 20,000 times in the columns next to A and B. So which loop effect would I need to use and how would the code look like ? This is honestly my first time attempting to use a loop macro