I don't totally understand it myself, which is why we were happy to let our DIL manage it. I do know we got Disney gift cards that she would use every day to buy genie+. You have to buy it every day, and it is dynamic pricing depending on how busy the parks are going to be. You can use your credit card, but since we were each paying for our own, the gift cards made it easy for her to get everyone's. With that you can get lightning lanes, but there are all kinds of rules about how many and how often you can get. Have no idea what those rules are, but she did. Some lightning lanes you have to pay an additional fee... the most popular ones. Then there are virtual queues for some rides. It's all crazy and you have to understand the whole system. I know there are videos that explain it all. Or if you're lucky like us, you can have a son and DIL who are total Disney nerds who go regularly and know what to do. It's truly a science.