You're responsible for taking appropriate measures to ensure that your confidential information, along with any personal data that's processed by the homeworker, is protected and remains secure. You must inform them of all of your rules concerning data confidentiality and protection, which should normally be contained in policies. They then must comply with those rules.
Ensure that the other members of the homeworker's household can't access any confidential information or personal data (e.g. by telling them to keep their devices locked with secure passwords when they aren't using them). You may need to carry out a data protection impact assessment with regards to homeworkers.
Require the homeworker to read any policies that you may have on Data protection. Also ensure you give any new versions of it, if and when it's amended.
They should also be provided with policies about IT security procedures, such as having and regularly changing passwords, downloading and installing security patches, and using adequate anti-virus software and firewalls. You should also provide them with rules on the use of electronic communications for work, such as email and social media.
The legislation governing data protection is the UK General Data Protection Regulation and the Data Protection Act 2018. For general information on this topic, see our data protection section.
You can also refer them to the Information Commissioner's Office's website, in particular its Guide to the GDPR.