Web 3 Hackathon as a beginner

Web 3 Hackathon

So our college is going to be one of the nodal centre of this national hackathon called HackIndia and it is going to happen in April . I have only 20 days or less than 20 to learn and then to think something out of the box related to web 3 or Blockchains . I am a complete beginner in Blockchain despite of this fact I want to participate as I have heard that the winner of previous hackIndia from our college was a complete beginner and he won the regional hackathon . Also when I asked him about the ideas , he said me and my team did lot of discussions and brain storming to achieve success in that idea . But I think he is lying because one of my close friends said he copied the idea from GitHub .I am thinking to try to implement an already built project which I have found in GitHub . Is this a very bad idea ? I am doing this because I want to participate and it's not possible for me to think and learn something that I am not much aware of but still I am trying to gain knowledge rn about those things . Please suggest me what should I do