Say hello to the perfect opportunity to build that Brooklyn business you’ve been dreaming about. Back for its 10th year, Brooklyn Public Library’s PowerUP! Business Plan Competition gives you a chance to win $15,000 in start-up cash. If you’re got a library card, then you’re almost there. First, you have to register and attend an orientation session at one of three branches across the borough. Then comes the fun part: The library helps you figure out what’s needed to get your business off the ground, and offers you access to a ton of resources so you can write a winning business plan, develop a marketing strategy for your idea or product and, importantly, find a way to bankroll your dream. And best of all, a business counselor will help you keep your eyes on the prize. Orientations run through April 4.