Shaff, welcome! I will try to help you out some. The first place to look would be the
YB/YBA FAQ thread on the main Fight Club page.
After the FAQ, you can check out the actual
YB rules page. There you'll find rules for character creation and detailed rules for gameplay.
After making up a name and possible back story for your fighting character, identify him as a white belt with 0 Yen, and a record of 0 wins and 0 losses. (see the
YB fighter registration page for how others keep track of their character info and also post your new character there for reference)
Then in the main Fight Club forum, post a new thread asking for someone to fight your character. (hint-state that you only want to fight other white belts for this fight. That way no black belts will come whip on your character. Although if you can win such a fight, the reward is sweet as you would get bumped up a number of ranks instantly. See the
YB Advancement table for the different ranks and tiers. White belts start at the bottom...)
When someone answers your challenge, you will exchange insults first (generated from the
YB Generator page). A judge will arrive to officiate the fight and judge the insults and moves. The winner of the insult round will choose the duration and type of match. (See the rules for details) Then you'll start generating opposing attacks from the 'Move' button on the above linked generator. The judge will decide the winner of each round and the fight will continue until someone wins enough flags to end the match.
If you get to the point of posting a challenge and I see that no one else has responded to it, I will make a new white belt character and answer your challenge so you can face an equal opponent.
Any other more specific questions that you can't find answers for in the FAQ or the rules, ask them here and I'll see if I can help some more. Hope you like the game!