I heard from someone that if you want to earn money without any investment then you should go to bitcointalk. But he also told me to keep alert. I created an account. I am feeling very confused but I am not able to understand anything.
Then keep alert...LOL
Your friend didn't lie to you, however he gave you a half baked information. He should be able to tell you that you need to contribute positively to the forum in order to rank up. When you rank up to atleast full member, you will be able to join signature campaign and start earning. Read the links people sent you and try your best to also learn from your friend that gave you the first information.
The problem is they always got interested about the profit, but they forgot to know what are the other things they need to learn from. Speaking about how to get profit is not the nicest thing or approach to be asked or even think of, since everything will fall apart especially if those guys didn't meet what they want to happen.
More better if they ask what Bitcoin also whole crypto is all about and how this forum work since once they get those knowledge then provably they can hit those targets they want and maybe can able to join on signature campaign in future. For now more better if he pays attention to learn a lot of information and try to build his account here. This is long process and patience is really needed since everything will be worth it in future especially if they exert a lot of effort to know more about the whole thing on what they are currently interested to try on.