The question of joining clans.

Hello. I have a question about clans. What are the criteria for joining a clan? How and why? Let's say I'm just some random guy 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 in-game test? I'm asking you to understand this correctly! I tried to find this information on the website/forum, but they are so extensive that it would take me a whole day 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!