You need to understand the difference between warnings and errors. A warning is the compiler telling you there is something in the code that could possibly cause a problem but doesn't cause the compilation to fail. An error is a problem with the code that causes compilation to fail. In this case you have posted warnings not errors.
It's a good idea to pay attention to warnings but these specific warnings don't indicate any potential problem so you are welcome to ignore them. If you prefer to fix them we can also help with that.