I want to create separate topics for each scam project!

Your best bet is to translate everything ^[English], prior to creating a thread in the "Scam Accusations board.

And I don't want to create an ICO announce!

It's not just about "translated ICO announcements". Pay attention to the following highlighted parts:

Quote from: hilariousandco on December 15, 2017, 09:52:28 AM
It is prohibited to create translated ICO threads for Local Languages that don't have their own sub boards. Due to abuse, it is also prohibited for users to create threads outside of their Local Thread. This sub forum is for those languages that don't have a local board to have their own thread to discuss bitcoin in; it is not a place for account farmers and spammers to easily abuse campaigns. If you post threads outside of your own local thread you will be banned.

How can we have a sub-board for Persian?

Nobody knows ^{[apart from @theymos]} the exact requirements, but the short answer is to have more activity ^{[as a whole]} in your local thread.