There are 6 things you need to do when employing staff for the first time:

1. Register as an employer with HM Revenue & Customs (HMRC) – you can do this up to 4 weeks before paying your staff.
2. Get employers’ liability insurance as soon as your become an employer.
3. Check if someone has the legal right to work in the UK.  You may need to carry out other employment checks as well.
4. Apply for a DBS check (Disclosure Barring Services Check) if you work in a field that requires one, eg with children, vulnerable people, etc.
5. Decide how much to pay someone – you must pay your employee at least the National Minimum Wage, dependent on the age of the employee.
6. Send the job description, including terms and conditions, in writing to your employee.  You also need to send a written contract of employment to your employee too.

Guidance and support for the above can be found on HM Revenue & Customs website:

https://www.gov.uk/browse/employing-people