I am a new member looking at enthusiastic friends who often show off the results of bitcoin, seems very profitable, I doubt help me for this
Welcome on board, this is a great place to learn about bitcoin and this technology. I would advise you to spend a month to just read the posts, as much as you can.
Now coming back to your topic, I think you shouldn't focus on profitability at the very first stage. Learn about it, see how it works, understand the usage and scope of it and then eventually try to engage with it. Bitcoin is a tool to enhance global economy with the elimination of limitations of fiat currencies, it's very less about speculations and 'make quick profit' sort of things imo.
As I always advise to everyone (including myself) that spending time worth $1 is always better than spending $100 if you want to learn something. Good luck.