Business mileage and self assessment

I get business mileage from a client i sub contract for, 25p a mile. I am not sure where/how i need to delcare this on my self assessment form? I've only done 2249 miles for them and paid on an agreed 25p a mile for this, so that equals £562.25 in total, this is the only mileage payment i get. Am new to this so am not certain where i need to delcare this?

Hi,
This would be included within your self employment section of the return to form part of your turnover.
Thankyou.