Registering for self assessment 2024/2015

I work full time, and in May 2024 I have started a side business. How do I officially let HMRC know? When I try to navigate self assessment pages; I can only find the option to submit a self assessment for 2023/24. But I don't need to do that

Hi,
To register for Self Employment, with your first year of filing being the 24/25 tax year, you can do so here - Check how to register for Self Assessment - or by
contacting us by webchat or phone via Self Assessment: general enquiries.
Thank you.