Self Assessment

Apologies if something similar has been posted previously but I am new to the forum!
I have recently set up my own business, but at the moment it is definitely earning less than £1,000 a year. I was advised to register for self assessment and have received a letter from HMRC asking me to submit a tax return for 2019-2020. When I spoke to an advisor on the phone he said because I was under the £1k threshold I would not need to include the income on the self assessment return.
However, I am in receipt (and have been for the last couple of years) of carer’s allowance for my autistic son.
I have gone online to complete the tax return but I don’t know where to start! Do I need to lump the very small earnings from my business in with the carers allowance?! Any assistance would be gratefully appreciated! Thank you.

There is a section on the Tax Return for taxable benefits. Carer’s Allowance goes in there.