The question of joining clans.

Good day. I have a question about clans. What are the criteria for joining a clan? How and why? Let's say I'm just an average person from a large city in Russia, and I want to walk around and brag that I'm a member of a Heroes 3 clan called "xxx"... Would I even be accepted into a clan, and if so, how? Is there some kind of test game? I would really appreciate it if you could explain this clearly! I tried to find this information on the website/forum, but they are so extensive that it would take me days to go through everything! If this topic is not relevant, please delete it, but please tell me the reason (220 530 919) if it's not too much trouble! Thank you in advance and sorry for the inconvenience!