https://www.slab.org.uk/faqs/step-1-get-ready-to-self-assess-against-the-organisational-standards/
https://www.slab.org.uk/faqs/step-1-get-ready-to-self-assess-against-the-organisational-standards/
Read the Self Assessment Guidance to help you identify what evidence the auditor will be looking for when you are audited.