Help with further learning

Hi Everyone, I have been doing basic server management and I'm looking to increase my knowledge to help with problems that may arise. I know there's plenty of threads on the forum however I'm more of a visual learner. I have looked on youtube and have failed to find tutorials that explain the following and what it does when you increase it: Apache Tuning Increasing MySQL Performance PHP Performance Tuning I know the basics of each but I'd like to learn & understand how to optimise these for performance for high-traffic sites. Does anyone know any free/paid courses or have access to videos for optimising these? Any help is appreciated Many Thanks