I agree with Ad Inserter being the best choice for beginners. If you have an ad code you want to place somewhere, go with them. I use that or another plugin on my smaller sites. Advanced Ads has a bit of a learning curve, but when I have multiple advertisers or campaigns and want to do a b testing and optimization then it comes with better usability and overview. It mirrors a bit how WordPress organizes its posts and doesn’t need coding skills to build advanced setup.