Plz guide me

Hello everybody i am a student and i am in my first year and i wanted to do competitive programming, i have few questions can you guys give me the answer of these questions 1) what to start first dsa or cp 2) if i complete dsa at a certain level so it would made easy to do cp 3) which courses should follow for dsa and cp 4) which specific set of problems should do in each rating(800,1000,1200) 5) how much problems should we do in each rating(800,1000,1200)