How to register myself as Self employed?

Not long ago I quit my task to begin a small organization. I do not be prepared to make hardly any money or pay myself everything for probably at the very least 4-6 months, so do i have to register myself as self-employed and the business for PAYE immediately?

My P45 says that i need to "register with HMRC within three months to become self-employed", but surely it is only when you're getting paid? I do not desire to make myself eligible to spend income-tax and nationwide insurance once I cannot personally have any such thing to arrive, and I also truly wouldn't like to have to fill in more paperwork easily can prevent it!

Can there be any such thing I need to do to let HMRC understand that We'll essentially be voluntarily unemployed for this duration? Is-it also really worth submitting a P50 in case i have overpaid back at my income tax from my past work?

Once the organization is making i am bound to get an accountant to simply help completely using this sort of thing, but right now I don't have the throwaway income to cover one, so any advice is considerably appreciated.