Which goes first stl or data structures and algorithms?
I think STL (assuming you mean C++ standard template library) is something you sort of learn as you use it. Exposure to DSA (data structures and algorithms) is essential for solving new problems or progressing in CS. Since you are just starting out and partial to C++, any DSA textbook in C++ will be a good reference. Just try to Google search “Data Structures and Algorithms C++,” maybe with your preferred file type.