They've told us that they have a way of carrying ranks over, but it will probably be a lengthy process, if they decide to carry them over. Everything else will be starting from scratch. Like Me_myslef_I said, all you really need to worry about is finding out when/where tournaments will be. If you already play at a regular tournament, nothing will change for you, with the exception of checking your record.
The meijins are being given registration cards with ID numbers and that will be your login ID.