Good, if you already know the basics how about you use your basic knowledge to work?
Judging by your answer you expecting someone to give you a step-by-step guide. And honestly if you really know the basics you know that there are no step-by-step guide to things like this.
There is no YouTube tutorials for that, there is only knowing what you wanna do and using the basics to try to that and learn more things as you get the results from what you have tried.
For example, a friend of mine called Gabriel found out a security breach on Facebook streams studying how the process of raiding streams works, how did he learned about it? Studying each and every variable that the event uses when that happened and so he found out he could redirect viewers from a stream to another without being admin in any of the pages.
As for how do you attack the target, there are many ways to attack someone. Just don't expect people to share these kind of information to the public like it is nothing.
CTFs are the basic, but if you want something easier than that what about
or
? These site have challenges for you to learn the basics of hacking with challenges to give you an idea on how to start. To test what you learned in the sites I recommended try to use the
that is a web application with lots of vulnerabilities on purpose for you to test your skills