You begin to " build " English in exactly the same way that you build a wall. First you lay a solid foundation on which to build. If the foundation is thin and weak, then the wall will surely collapse.
To build a solid English language wall you MUST start of with a solid foundation, and this means by REALLY learning the basics.
Personal Pronouns are your " mix ". Just add time and patience, mix well, and off you go. Once your mix has developed and set solid, then you are on your way to start building your wall.
Without proper preparation you will surely fail. With proper preparation, then the sky is your limit.!