i know basic c++ where do i start?

hi im joel 16 years old i know basic c++ i started learning it online and have spent a week reading but i finaly got over the basics. what i found was its all just a lot of algebra and high school math. now my problem is i don't know where to start!!!! like what are addys how do i transfer my codes into a dll and how to modify existing hacks to my os.i feel realy lost and need some information help is much appreciated