Hello, a friend recommended me this website (too late I think), how can I gain more “security” or “confidence”? He also told me something about organizing my profile but I'm totally new, thank you all very much.

Welcome!

For your first trades (and all future trades), you can rely on the Mediation system: https://forums.d2jsp.org/info.php?c=4&p=11

Trusted users will facilitate a transaction between two traders by holding the forum gold during the exchange. So if anyone has doubts, then you can always request a mediator trade to ensure 100% safety.

And yes, beyond that, putting effort into one's profile may also help with being taken seriously, but it's not really a requirement.

Welcome

Nice little guide here -->New User Guide - https://forums.d2jsp.org/topic.php?t=63392948