How to identify HMRC related scams
https://www.gov.uk/guidance/identify-hmrc-related-scam-phone-calls-emails-and-text-messages 

Being a director
https://www.gov.uk/guidance/being-a-company-director

Running a limited company
https://www.gov.uk/running-a-limited-company

Tax on dividends
https://www.gov.uk/tax-on-dividends

National Insurance for company directors
https://www.gov.uk/employee-directors

Employee’s (primary) Class 1 NI rates
https://www.gov.uk/government/publications/autumn-statement-2023-overview-of-tax-legislation-and-rates-ootlar/annex-a-rates-and-allowances

National Insurance guidance for directors
CA44: National Insurance for company directors – GOV.UK (www.gov.uk)

Understanding off-payroll working (IR35)
https://www.gov.uk/guidance/understanding-off-payroll-working