First you have to make a bio wich requires 50 posts. Once you read that amount of posts, you can go
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and create a new thread.
Once you clicked the "New Thread" button, you have to copy/paste
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into it and fill the template in. While you fill it in, make sure that your bio does follow the rules wich are stated
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Once your biography is apporved (yes you must wait for getting it approved) you can start training. Therefore you need a sensei or sempai. Sensei can be found in the forum section and if you scroll down completely you find all active members. Orange named people are the senseis. You can go to their profile and ask for training. If they are full you must wait or go to their sempai if they have one. The sempai's name is often written on the sempais profile.
Once you have been trained, you can start and battle in the section you posted this thread in.
But be aware of the fact that this thread was made in the wrong section and should be posted in the "Question & Suggestion" section.