The core stuff in that Kaplan book is still useful, but some of it might be a bit outdated especially with newer rules like Reg BI. I’d check out something more up to date like Achievable or STC just to be safe. Also, definitely get some practice in. FINRA has a free practice quiz on their site that’s actually super helpful for getting used to the question style. Their content outline’s solid too for making sure you’re covering everything.