How should a beginner start contributing to open source projects, and what prerequisites are needed?

I am a computer science student with knowledge of Java, Spring Boot, React, JavaScript, and basic Git/GitHub usage. I want to start contributing to open source projects, but I feel overwhelmed by large codebases and do not know the correct starting path. I would like guidance on: What skills are expected before making first contributions How to find beginner-friendly repositories/issues Whether I should focus on documentation fixes first or code contributions How much Git/GitHub knowledge is required How experienced developers understand large existing codebases I have built some personal proj