I am going to a hackathon for the first time with little knowledge (or u can say no knowledge) what advice can anyone can give so that I don't screw it up and how can I learn new things?

Just get involved! Hackathons are great for learning new things. Don't be afraid to talk to people and ask people to explain stuff to you. Most importantly have fun :)

Just let the atmosphere inspire yourself. Collect ideas and try to get an insight into new technics. There is no shame to be a newbie...and to be honest (I was hackcoach on a huge hackathon three times) the new folks are actually often the most enthusiastic participants with not that narrow technical mindset