How to calculate NIC2 and NIC4 if I have more than one businesses in the tax year

Hi HMRC, In the tax year 2022-2023, I worked as self employed. From April to July, I ran my business called A and then it ceased on 31 July 2023. The total earnings for business A was £8200. Then I started another business B as delivery driver (self employed) in Jan 2023, and the earnings upto 6 April 2023 was £4000. May I know how do I calculate NIC 2? Should I count the total earnings of business A and B in the tax year? The total earnings for A & B exceed £11098 then I should pay NIC2 £3.15 x 52 = £163.5 ? OR, Should I look into the NIC2 separately for two businesses? If yes, business A earnings was above Small Profits Threshold £6,725 while business B earnings was below the Small Profits Threshold. In this case, I no need to pay NIC2? In any circumstances of the above, I don't have to pay NIC4 right?

Hi,
You will need to contact HMRC to cease the first business and re-register for the second.
You can do this on line:
Set up as self-employed (a 'sole trader'): step by step 
Thankyou.