Hi, are you able to ask your setting for the policy and procedures that cover this? They will have one. It will lay out how all staff members are expected to respond to any allegation and the notification periods relating to Ofsted.
For example, should a parent come to you with an allegation, your setting might expect you to refer them to more senior management or the person responsible for safeguarding in your setting, you would be expected to maintain confidentiality, report and record any information you have and maybe be part of future meetings if that is appropriate.
If it helps in the meantime
page 92+ of this EYE handbook is good reading.
and
section 3 of the EYFS frameworrk (if you're working in england) under Child Protection page 23 states this about notification periods:
3.8. Registered providers must inform Ofsted or their childminder agency of any allegations of serious harm or abuse by any person living, working, or looking after children at the premises (whether the allegations relate to harm or abuse committed on the premises or elsewhere). Registered providers must also notify Ofsted or their childminder agency of the action taken in respect of the allegations. These notifications must be made as soon as is reasonably practicable, but at the latest within 14 days of the allegations being made. A registered provider who, without reasonable excuse, fails to comply with this requirement, commits an offence.
Hope this helps, all the best xx