new player

so im new and i did actually downloaded the game 6 months ago and finish the easy or normal. the thing is i still dont understand a lot of thing in poe but i love this game as it reminds me of diablo which i played the second of so can u guys explain things like how to clan/guilds work,trading works and so on btw if im posting in a wrong place im sorry and also ty for giving me any information ty

Beginner myself but I am trying to answer your two questions:

You can join a guild by getting invited. There is an extra chat channel you can talk to your guild members then. Also guild stash tabs if the guild has any.

Searching for a guild here in the forums or ingame in The Global Chat Channel #100 the official Guild Recruitment Channel. To access it type /global 100 in your chat window.

For trading there is a trade channel ingame, or a extra section here in the forums, or the official website for it "poe.trade".

Trading is in a very controversial state right now. The easiest way to find items to buy and sell your own items is to be actively using and going to poe.trade. It is an allowed third party website that reads the shops set up through procurement or acquisition programs which are free but also third party (very trustworthy so far as well. Both are open source and the only accusations of being hacked due to these programs have literally disappeared among the forum threads because people found a lot of flaws in their argument and stopped caring to entertain their delusions). Otherwise you can purchase premium stash tabs that can be made public and are added to poe.trade's scans a bit quicker than the third party programs. After that, trade is nothing more than a single screen where each party hovers over the other's offer and is then able to accept. So be cautious when trading for switches both during and at the start of a trade if something seems off.

ty for your reply