What’s on your to-do list for when you win the massive $1.5 billion Powerball jackpot? The sheer size of the big prize to be drawn Saturday night probably has even the most pragmatic among us dreaming about what it would be like to win. However you think you’d spend the money, financial advisors agree on one thing: Take your time. “Don’t start making big purchases right away,” said Alexandra Makowski, a certified financial planner with CFS Investment Advisory Services in Totowa. “Wait a few months to settle in to the new reality of the wealth you now have. Learn from the mistakes of other weal…